Consider allowing x|=0 as a valid Parameter Type Annotation

[srijs]

Hi!

Uglify.js and other js compressors translate a pattern like x=x|0 into x|=0 because it is one byte shorter. Unfortunately, this breaks asm.js code that is minified with one of those tools.

Regarding to the EcmaScript standard, those two seem to be funtionally equivalent, so I was wondering if it would be possible to make the asm.js spec more lenient by allowing x|=0 to be a valid parameter type annotation?