Keep Optimization Remark Yaml in NewPM

Keep Optimization Remark Yaml in NewPM

Summary:
The New Pass Manager infrastructure was forgetting to keep around the optimization remark yaml file that the compiler might have been producing. This meant setting the option to '-' for stdout worked, but setting it to a filename didn't give file output (presumably it was deleted because compilation didn't explicitly keep it). This change just ensures that the file is kept if compilation succeeds.

So far I have updated one of the optimization remark output tests to add a version with the new pass manager. It is my intention for this patch to also include changes to all tests that use `-opt-remark-output=` but I wanted to get the code patch ready for review while I was making all those changes.

Fixes https://bugs.llvm.org/show_bug.cgi?id=33951

Reviewers: anemet, chandlerc

Reviewed By: anemet, chandlerc

Subscribers: javed.absar, chandlerc, fhahn, llvm-commits

Differential Revision: https://reviews.llvm.org/D36906

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311271 91177308-0d34-0410-b5e6-96231b3b80d8