[Interpreter] Multiple input files for generate-bytecode-expectations.

When operating in --rebaseline mode, each of the files will be updated.
In --raw-js mode, all the expectations will be written to the same file.
In default mode no more than one input file is accepted.

On POSIX systems, --rebaseline will autodiscover golden files when run
from the project root and no input file is provided.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1737623002

Cr-Commit-Position: refs/heads/master@{#34324}