post push fix, Bug#38719, additional test cases updated

handler::get_dup_key used the called handler for the
info call, but used table->file handler for errkey.
Fixed by using table->file->info instead.

Backport from 6.0

Changed error message to show that it is partitioning
that does not support foreign keys yet.

Changed spelling from British english to American english.

      
Removed the misleading "NOTE:" from the \h command. 

replace wild_case_compare with my_wildcmp which is multibyte safe function

stack reservation too small

Problem: some tests fail on HP-UX due to insufficient stack reservation.

Fix: increase stack reservation.

Cleaned up SQL code in the test.
Needed to move the FLUSH TABLES statement prior to the DROP TABLE t1 to prevent a warning of
Table open on delete and a test fail.

Dirty close tricky does not work on Windows.

Bug#38435 - LONG Microseconds cause MySQL to fail a CAST to DATETIME or DATE

Parsing of optional microsecond part in datetime did not
fail gracefully when field width was larger than the allowed
six places.

Now handles up to the correct six places, and disregards
any extra digits without messing up what we've already got.