Move HeapProfiler parameters into a separate class

This will make it easier to expand the parameter parsing in a followup,
to allow separate parameters for each type of subprocess.

R=lizeb

Bug: 1327069
Change-Id: I969b1c8244cdce073789e913787bc09c593f549e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3863677


Auto-Submit: Joe Mason <joenotcharles@google.com>
Commit-Queue: Joe Mason <joenotcharles@google.com>
Reviewed-by: Benoit Lize <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1042720}