Improving an error report generating.

Backporting the basic tests

backporting from 6.0 code base to 5.1.

There is a missing check for memory allocation failure when allocating
memory for the handlerton structure. If the handlerton init function
tries to de-reference the pointer, it will cause a segmentation fault
and crash the server.

This patch fixes the problem by not calling the init function if memory
allocation failed, and instead prints an informative error message and
reports the error to the caller.

            
Adding header include file guards to files that are missing such.

When setting AUTOCOMMIT=1 after starting a transaction, the binary log
did not commit the outstanding transaction. The reason was that the binary
log commit function saw the values of the new settings, deciding that there
were nothing to commit.

Fixed the problem by moving the implicit commit to before the thread option
flags were changed, so that the binary log sees the old values of the flags
instead of the values they will take after the statement.

slave leaves slave unstable

Problem: when replicating from non-transactional to
transactional engine with autocommit off, no BEGIN/COMMIT
is written to the binlog. When the slave replicates, it
will start a transaction that never ends.

Fix: Force autocommit=on on slave by always replicating
autocommit=1 from the master.

Extract substr into local variable

with the newer pb2 testing environments

a "if"
Bug #41913 mysqltest cannot source files from if inside while
Some commands require additional processing which only works first time
Keep content for write_file or append_file with the st_command struct
Add tests for those cases to mysqltest.test

This fixes the regression introduced in 5.1 that prevents 64 bit builds on Intel while still keeping the core2 hack operational so the cluster can build.

Remove a self assignment.
Rework a few constructs to avoid a potential overflow.

Based upon patch contributed by Michal Hrusecky

On 64-bits machines the calculation gets the wrong types and results
in very large numbers. Fixed by explicitly cast month to (int)