[obj2yaml] - Stop triggering UB when dumping corrupted strings.

We have a following code to find quote type:

if (isspace(S.front()) || isspace(S.back()))

Problem is that:

"int isspace( int ch ): The behavior is undefined if the value of
ch is not representable as unsigned char and is not equal to EOF."

This patch shows how this UB can be triggered and fixes an issue.

Differential revision: https://reviews.llvm.org/D69160

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375404 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed