Allow alternate golden images for TestWithGoldenOutput

Since build flags could change the output to be checked, it's
good to have the ability to check against different sets of
golden outputs and find one that matches.

This solves the problem of having some builds using
RELEASE_TARGET_JAVA_21 and others not.

Fixes: 378470825
Test: atest --host tiny-framework-dump-test:__main__.TestWithGoldenOutput#test_compare_to_golden
Change-Id: I1b10e4b65673b351fe70a04cb2bf6ba58e0878cd