[llvm-branch-commits] [BOLT][NFCI] Simplify DataAggregator using traces (PR #138181)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/138181

Trace is a triple of (branch source, branch target, fallthrough end),
introduced in https://github.com/llvm/llvm-project/pull/127125.

Use traces throughout branch profile handling, unifying perf parsing
and pre-aggregated format handling. This in turn makes it possible to
use pre-aggregated data for heatmaps.

Test Plan: NFCI