The gmock matchers have a concept of MatchAndExpain; where the details of the
matching are written to a "result listener". A matcher can avoid creating
expensive debug info by checking result_listener->IsInterested(); but,
unfortunately, the default matcher code (called from EXPECT_THAT) is always
"interested".

This change implements EXPECT_THAT matching to first run the matcher in a "not
interested" mode; and then run it a second time ("interested") only if the
match fails.

PiperOrigin-RevId: 225036073