sanitizer_common: avoid compiler-interted memset in deadlock detector

Compilers tends to insert memset/memcpy for some struct/array operations,
and these don't play well inside of sanitizer runtimes.
Avoiding these calls was the intention behind internal_memset.
Remove the leftover ={} that can result in memset call.

Reviewed By: vitalybuka, pgousseau

Differential Revision: https://reviews.llvm.org/D106978

compiler-rt/lib/sanitizer_common/sanitizer_mutex.cpp

@@ -73,7 +73,7 @@ void DebugMutexInit() {
   // Build adjacency matrix.
   bool leaf[kMutexTypeMax];
   internal_memset(&leaf, 0, sizeof(leaf));
-  int cnt[kMutexTypeMax] = {};
+  int cnt[kMutexTypeMax];
   internal_memset(&cnt, 0, sizeof(cnt));
   for (int t = 0; t < kMutexTypeMax; t++) {
     mutex_type_count = t;