Allow the C++ toolchain config rules comparator script to not need toolchain_identifier argument when both --before and --after arguments are CToolchains (coming from Starlark rules instead of CROSSTOOL proto)
Allow the C++ toolchain config rules comparator script to not need toolchain_identifier argument when both --before and --after arguments are CToolchains (coming from Starlark rules instead of CROSSTOOL proto)

We don't need to select a toolchain by the identifier when we get the proto from Starlark rules because in that case the proto contains a single toolchain.
The difference in toolchain_identifier field between the first and the second proto file will be caught as any other field.

RELNOTES: None.
PiperOrigin-RevId: 262543753
Change-Id: I1e66ee302bf551ade883c217f6269f44382393c0

bazelbuild/rules_cc,bazelbuild/rules_cc,bazelbuild/rules_cc,bazelbuild/rules_cc