CTestTestMemcheck: Refactor output expectation regex generation
CTestTestMemcheck: Refactor output expectation regex generation

Refactor generation of PASS_REGULAR_EXPRESSION for tests

 CTestTestMemcheckDummyPurify
 CTestTestMemcheckDummyValgrind
 CTestTestMemcheckDummyValgrindPrePost
 CTestTestMemcheckDummyValgrindIgnoreMemcheck

Avoid duplicating the normal ctest output matching expression.  Use
literal newlines instead of "\n" to improve readability.  Integrate
matching of guard-malloc lines at the end of the output with expressions
matching tool output like lines for BullseyeCoverage.
CTestTestMemcheck: Tolerate trailing "==..." lines from valgrind
Merge topic 'cleanup-CTestTestMemcheck' into next

43bcd88 CTestTestMemcheck: Refactor output expectation regex generation
Merge topic 'cleanup-CTestTestMemcheck' into next

158d1ed CTestTestMemcheck: Tolerate trailing "==..." lines from valgrind
7aae9ee CTestTestMemcheck: Refactor output expectation regex generation