[fuzz coverage] Remote coverage.py dependency from merge_all_fuzzers.py.

The profdata file that coverage.py *exports* is different than what it
uses to generate coverage locally, causing a divergence in behavior of
the local coverage script and the recipe run for coverage in automation.

Plus, coverage.py is far too heavyweight for what we need anyway.

Replace coverage.py with a simple llvm-profdata merge command.

Change-Id: Icd8c8f52abb214399395e4d82a34f71fa2bc1329
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4657425
Reviewed-by: Prakhar Asthana <[email protected]>
Commit-Queue: Julia Hansbrough <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1166687}
NOKEYCHECK=True
GitOrigin-RevId: 2f7fe7135bd8469159e341fab9c12858d9d3d487
1 file changed