[clang] [Clang][perf-training] Do build of libLLVMSupport for perf training (PR #111625)

[Tom Stellard via cfe-commits]

tstellar wrote:

> I'm assuming you used instrumented BOLT here? Also, do you have numbers on how long the perf training took?

Yes, it was instrumented BOLT. I've added the perf training times to the commit summary.



https://github.com/llvm/llvm-project/pull/111625