Improve the efficiency of bytecode generated for CharClass.

Change-Id: Ibf00ad9575ae800eedfc1c0f0a440fae261dce53
Reviewed-on: https://code-review.googlesource.com/4040
Reviewed-by: Russ Cox <rsc@swtch.com>
Reviewed-by: Paul Wankadia <junyer@google.com>
2 files changed