[asan,tsan,msan] move the memcmp interceptor from asan/tsan to...

[asan,tsan,msan] move the memcmp interceptor from asan/tsan to sanitizer_common. This may potentially lead to more reports from msan as it now sees the reads inside memcmp. To disable, use the flag intercept_memcmp=0. Likewise, it may potentially cause new races to appear due to more strict memcmp checking (flag strict_memcmp=1)

llvm-svn: 243595