This change adds an API to allow setting the flag to indicate that the profile data has been dumped to the file.

Summary:
The main use is for users to disable dumping profile data to the file
for certain processes in case the processes don't have permission to
write to the disks, and trying to do so would result in side effects
such as crashes.

Patch by Yuke Liao (@liaoyuke).

Additional context (Chromium use case):
- https://bugs.chromium.org/p/chromium/issues/detail?id=842424
- https://bugs.chromium.org/p/chromium/issues/detail?id=957655
- https://chromium-review.googlesource.com/c/chromium/src/+/1610093

Reviewers: Dor1s, vsk, davidxl

Reviewed By: Dor1s, davidxl

Subscribers: delcypher, davidxl, sajjadm, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D62078

llvm-svn: 361194