Restore old labeled break semantics

It seems jshint sometimes gets in an infinite loop; apparently the rewrite of https://github.com/ajaxorg/ace/pull/1259 wasn't completely accurate. This rewrites the labeled break to more closely match the original semantics (see the [diff](https://github.com/ajaxorg/ace/compare/83be0083bb4a192ecd2298bfd71479da369c9662...fix-100pct-cpu#L5L1926)). 

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