fix for Bug #55672 "mysql_upgrade dies with internal error":

it couldn't parse the --ssl option.

client/mysql_upgrade.c:
  mysql_upgrade parses its options and passes some of them to the underlying
  tools (mysqlcheck etc). To do this passdown, it reconstructs a
  command-line-suitable text from the my_option object (which
  contains the option's name and option's value). For options
  which expect no parameter, it just had to use the option's name;
  for other options, it had to concatenate the option's name,
  a "=" symbol, and the option's value; it had code to handle
  this latter case, but only for GET_STR options (options taking a
  string as value). But since the work on WL 4738, the --ssl
  option, a GET_BOOL, which used to have no parameter (NO_ARG), can
  now have one (OPT_ARG), so with --ssl we came to the "default"
  label, error. Fixed by constructing the command-line-suitable
  representation for GET_BOOL too. For --ssl it will produce
  --ssl=1 ; for --ssl=0, it will produce --ssl=0.
mysql-test/include/mysql_upgrade_preparation.inc:
  handles requirements of tests which use mysql_upgrade
mysql-test/r/mysql_upgrade_ssl.result:
  result; without the code fix we would get "internal error".
mysql-test/t/mysql_upgrade.test:
  This test has requirements before running; moved them
  to an include file in order to share with mysql_upgrade_ssl.
mysql-test/t/mysql_upgrade_ssl.test:
  test for bug. Couldn't go into mysql_upgrade.test as this new test requires
  SSL support. --force is needed, in case mysql_upgrade.test run before
  (in which case mysql_upgrade_ssl would say that upgrade has already been
  done); --force forces the upgrade in all cases.

mysql-test/include/mysql_upgrade_preparation.inc

@@ -0,0 +1,30 @@
+# Include this in any test using mysql_upgrade
+
+# Can't run test of external client with embedded server
+-- source include/not_embedded.inc
+
+# Only run test if "mysql_upgrade" is found
+--require r/have_mysql_upgrade.result
+--disable_query_log
+select LENGTH("$MYSQL_UPGRADE")>0 as have_mysql_upgrade;
+--enable_query_log
+
+#
+# Hack:
+#
+# If running with Valgrind ($VALGRIND_TEST <> 0) then the resource
+# consumption (CPU) for upgrading a large log table will be intense.
+# Therefore, truncate the log table in advance and issue a statement
+# that should be logged.
+#
+if (`SELECT $VALGRIND_TEST`)
+{
+  --disable_query_log
+  --disable_result_log
+  --disable_abort_on_error
+  TRUNCATE TABLE mysql.general_log;
+  SELECT 1;
+  --enable_abort_on_error
+  --enable_result_log
+  --enable_query_log
+}