Further refine the Java syntax lexer for escaped strings
Further refine the Java syntax lexer for escaped strings

Summary:
Ref T13210. See PHI886. Previously, D19731 improved some behavior here, but didn't go quite far enough and we still got strings with `\"` wrong.

Parse backslash followed by anything, or any character except double quote or backslash.

(If this is still somehow wrong I can just copy one of the other lexers which is a little more complicated but gets this right.)

Test Plan: {F5963219}

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13210

Differential Revision: https://secure.phabricator.com/D19763

aik099/libphutil,Khan/libphutil,aik099/libphutil,uber/libphutil,Khan/libphutil,wikimedia/phabricator-libphutil,uhd-urz/libphutil,Khan/libphutil,codelabs-ch/libphutil,codelabs-ch/libphutil,devurandom/libphutil,uber/libphutil,wikimedia/phabricator-libphutil,wikimedia/phabricator-libphutil,uber/libphutil,uhd-urz/libphutil,uhd-urz/libphutil,aik099/libphutil,codelabs-ch/libphutil,devurandom/libphutil,devurandom/libphutil