[libfuzzer] Compare TotalNumberOfRuns with MaxNumberOfRuns when testi…

…ng a memory leak.

Summary:
Fuzzer::TryDetectingAMemoryLeak may call ExecuteCallback which would
increment TotalNumberOfRuns, but it doesn't respect Options.MaxNumberOfRuns
value specified by a user.

Context: google/oss-fuzz#822 (comment)

Reviewers: kcc

Reviewed By: kcc

Differential Revision: https://reviews.llvm.org/D37632

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@312993 91177308-0d34-0410-b5e6-96231b3b80d8

FuzzerLoop.cpp

@@ -525,6 +525,8 @@ void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
                                      bool DuringInitialCorpusExecution) {
   if (!HasMoreMallocsThanFrees) return;  // mallocs==frees, a leak is unlikely.
   if (!Options.DetectLeaks) return;
+  if (!DuringInitialCorpusExecution &&
+      TotalNumberOfRuns >= Options.MaxNumberOfRuns) return;
   if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
       !(EF->__lsan_do_recoverable_leak_check))
     return;  // No lsan.