[test-suite] Add cmake option to use IR PGO (TEST_SUITE_USE_IR_PGO)

This allows building programs in the test suite with LLVM's IR PGO
feature. Support for re-building programs with the collected profdata is
already present.

Differential Revision: https://reviews.llvm.org/D57985

git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@353591 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed