Problem:
sql_print_information crashes the server if the length of the string is more
than 8192 bytes which will result of truncation. Invalid memory was accessed
which resulted in core dumps.

Solution:
Introduced a check for overflowing buffers in log.cc:log_vmessage

Made a testcase in log_sink_test.cc that inputs a larger than
buffer in the error message.

Recorded associated log_sink_test tests.Bug #31686926 - SQL_PRINT_INFORMATION CRASHES IF THE LENGTH MORE THAN 8192 BYTES

Problem:
sql_print_information crashes the server if the length of the string is more
than 8192 bytes which will result of truncation. Invalid memory was accessed
which resulted in core dumps.

Solution:
Introduced a check for overflowing buffers in log.cc:log_vmessage

Made a testcase in log_sink_test.cc that inputs a larger than
buffer in the error message.

Recorded associated log_sink_test tests.

Change-Id: Ib923e0ab8a8ecc5205449b861cb0b358c1af0daa