Merge 10.6 into 10.10

The MDEV-29693 conflict resolution is from Monty, as well as is
a bug fix where ANALYZE TABLE wrongly built histograms for
single-column PRIMARY KEY.
Also includes a fix for safe_malloc error reporting.

Other things:
- Copied main.log_slow from 10.4 to avoid mtr issue

Disabled test:
- spider/bugfix.mdev_27239 because we started to get
  +Error	1429 Unable to connect to foreign data source: localhost
  -Error	1158 Got an error reading communication packets
- main.delayed
  - Bug#54332 Deadlock with two connections doing LOCK TABLE+INSERT DELAYED
    This part is disabled for now as it fails randomly with different
    warnings/errors (no corruption).

sql/sql_base.h

@@ -130,6 +130,9 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
 */
 #define MYSQL_OPEN_IGNORE_LOGGING_FORMAT        0x20000
 
+/* Don't use statistics tables */
+#define MYSQL_OPEN_IGNORE_ENGINE_STATS          0x40000
+
 /** Please refer to the internals manual. */
 #define MYSQL_OPEN_REOPEN  (MYSQL_OPEN_IGNORE_FLUSH |\
                             MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK |\
@@ -650,7 +653,7 @@ class No_such_table_error_handler : public Internal_error_handler
 {
 public:
   No_such_table_error_handler()
-    : m_handled_errors(0), m_unhandled_errors(0)
+    : m_handled_errors(0), m_unhandled_errors(0), first_error(0)
   {}
 
   bool handle_condition(THD *thd,
@@ -665,11 +668,11 @@ public:
     trapped and no other errors have been seen. FALSE otherwise.
   */
   bool safely_trapped_errors();
+  uint got_error() { return first_error; }
 
 private:
   int m_handled_errors;
   int m_unhandled_errors;
+  uint first_error;
 };
-
-
 #endif /* SQL_BASE_INCLUDED */