[msan] getaddrinfo & nested interceptor support.

Multiple connected changes:
- Ignore reads from nested interceptors.
- Check shadow on reads from common interceptors.
- getaddrinfo interceptor.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@182466 91177308-0d34-0410-b5e6-96231b3b80d8