[asan/tsan] when unmapping a chunk of user memory, apply madvise(MADV_DONTNEED) to the corresponding chunk of shadow memory. Also update sanitizer_allocator64_testlib.cc

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@171144 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed