Remove memrchr() and the logic that calls it.

The DFA execution engine can run backwards unanchored, but RE2 only ever
needs it to run backwards anchored, so there's no need for memrchr().

Change-Id: I77a53293f4d6422ecd55760100a70e951ac5fb7f
Reviewed-on: https://code-review.googlesource.com/c/re2/+/55070
Reviewed-by: Paul Wankadia <junyer@google.com>
1 file changed