…e GC specification

Currently memory_profile_stable_heap_parameters expects 2 ints and runs that
many GCs with pauses between them 2nd param.

This CL doesn't change that, but allows any arbitrary number of pairs to be
provided that will run the same logic for each pair.  This allows experimenting
with forcing longer pauses on that thread before doing the quick GCs that allow
for cleaner memory measurement.

PiperOrigin-RevId: 485646588
Change-Id: Iff4f17cdaae409854f99397b4271bb5f87c4c404

Fixes bazelbuild#3054

RELNOTES: Options specified on the pseudo-command `common` in `.rc` files are now ignored by commands that do not support them as long as they are valid options for *any* Bazel command. Previously, commands that did not support all options given for `common` would fail to run. These previous semantics of `common` are now available via the new `always` pseudo-command.

Closes bazelbuild#18130.

PiperOrigin-RevId: 534940403
Change-Id: I2ae268ae84de3f2b07ff3d1e36bf382bce714968