[asan] convert a CHECK failure in __sanitizer_annotate_contiguous_container into a proper warning message

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@197899 91177308-0d34-0410-b5e6-96231b3b80d8
[asan] clean up at the end of the shmget/shmctl test

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@197901 91177308-0d34-0410-b5e6-96231b3b80d8