[llvm-branch-commits] [llvm-profgen] Add --time-profgen (PR #191930)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/191930

Add `NamedRegionTimer`s to main profgen phases:
- Parse and aggregate trace (`parseAndAggregateTrace`)
- Unwind samples (`unwindSamples`)
- Generate profile (`ProfileGenerator::generateProfile`)
- Generate CS profile (`CSProfileGenerator::generateProfile`)

Test Plan:
```
$ llvm-profgen --time-profgen ...

===-------------------------------------------------------------------------===
                                  llvm-profgen
===-------------------------------------------------------------------------===
  Total Execution Time: 2826.6549 seconds (2873.3410 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
  1059.4929 ( 38.1%)   8.5146 ( 17.3%)  1068.0075 ( 37.8%)  1090.6604 ( 38.0%)  Generate CS profile
  892.6504 ( 32.1%)  39.8720 ( 80.9%)  932.5224 ( 33.0%)  950.7938 ( 33.1%)  Parse and aggregate trace
  825.2141 ( 29.7%)   0.9110 (  1.8%)  826.1250 ( 29.2%)  831.8868 ( 29.0%)  Unwind samples
  2777.3573 (100.0%)  49.2975 (100.0%)  2826.6549 (100.0%)  2873.3410 (100.0%)  Total
```