Fixing a possible memory leak from a failing realloc() call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195018 91177308-0d34-0410-b5e6-96231b3b80d8
Checking for a return value with FormatMessage; if the call fails, there's no guarantee that the buffer will be non-null.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195019 91177308-0d34-0410-b5e6-96231b3b80d8