[YDBTest#450] Add WBTEST_YDB_MAXSECSHRRETRY white box code to test gtmsecshr communication error

A new v63013/gtm9278 test in YDBTest repo (YDBTest!1470 (merged)) uses the new white box code introduced in this commit to cause the gtmsecshr communication loop in secshr_client.c to fail without even entering the loop by resetting the maximum loop count to the max+1 before entering the loop. This causes the code to fall into the timeout error code driving the messages our test needs to see.