Fix all warnings given by UBSAN

The easiest way to compile and test the server with UBSAN is to run:
./BUILD/compile-pentium64-ubsan
and then run mysql-test-run.
After this commit, one should be able to run this without any UBSAN
warnings. There is still a few compiler warnings that should be fixed
at some point, but these do not expose any real bugs.

The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
  complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
  memory access of integers.  Fixed by using byte_order_generic.h when
  compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
  disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
  suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
  safe to have overflows (two cases, in item_func.cc).

Things fixed:
- Don't left shift signed values
  (byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
  constructors.  This was needed as UBSAN checks that these types has
  correct values when one copies an object.
  (gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
  deleted objects.
  (events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
  on Query_arena object.
- Fixed several cast of objects to an incompatible class!
  (Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
   sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
  This includes also ++ and -- of integers.
  (Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
  value_type is initialized to this instead of to -1, which is not a valid
  enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.
- Fixed that Item_func_str::make_empty_result() creates an empty string
  instead of a null string (safer as it ensures we do not do arithmetic
  on null strings).

Other things:

- Changed struct st_position to an OBJECT and added an initialization
  function to it to ensure that we do not copy or use uninitialized
  members. The change to a class was also motived that we used "struct
  st_position" and POSITION randomly trough the code which was
  confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
  the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
  avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr.  (This variable was before
  only in 10.5 and up).  It can now have one of two values:
  ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
  it virtual. This was an effort to get UBSAN to work with loaded storage
  engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
  in tabutil.cpp.
- Added HAVE_REPLICATION around usage of rgi_slave, to get embedded
  server to compile with UBSAN. (Patch from Marko).
- Added #ifdef for powerpc64 to avoid a bug in old gcc versions related
  to integer arithmetic.

Changes that should not be needed but had to be done to suppress warnings
from UBSAN:

- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
  compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
  some compile time warnings.

Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes & Embedded server: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia

sql/temporary_tables.cc

@@ -1,5 +1,5 @@
 /*
-  Copyright (c) 2016, 2019, MariaDB Corporation.
+  Copyright (c) 2016, 2021, MariaDB Corporation.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -875,10 +875,12 @@ void THD::restore_tmp_table_share(TMP_TABLE_SHARE *share)
 inline bool THD::has_temporary_tables()
 {
   DBUG_ENTER("THD::has_temporary_tables");
-  bool result= (rgi_slave
-                ? (rgi_slave->rli->save_temporary_tables &&
-                   !rgi_slave->rli->save_temporary_tables->is_empty())
-                : (has_thd_temporary_tables()));
+  bool result=
+#ifdef HAVE_REPLICATION
+    rgi_slave ? (rgi_slave->rli->save_temporary_tables &&
+                 !rgi_slave->rli->save_temporary_tables->is_empty()) :
+#endif
+    has_thd_temporary_tables();
   DBUG_RETURN(result);
 }
 
@@ -1508,12 +1510,14 @@ bool THD::lock_temporary_tables()
     DBUG_RETURN(false);
   }
 
+#ifdef HAVE_REPLICATION
   if (rgi_slave)
   {
     mysql_mutex_lock(&rgi_slave->rli->data_lock);
     temporary_tables= rgi_slave->rli->save_temporary_tables;
     m_tmp_tables_locked= true;
   }
+#endif
 
   DBUG_RETURN(m_tmp_tables_locked);
 }
@@ -1534,6 +1538,7 @@ void THD::unlock_temporary_tables()
     DBUG_VOID_RETURN;
   }
 
+#ifdef HAVE_REPLICATION
   if (rgi_slave)
   {
     rgi_slave->rli->save_temporary_tables= temporary_tables;
@@ -1541,6 +1546,7 @@ void THD::unlock_temporary_tables()
     mysql_mutex_unlock(&rgi_slave->rli->data_lock);
     m_tmp_tables_locked= false;
   }
+#endif
 
   DBUG_VOID_RETURN;
 }