Simplify boolean expressions in Java AST

[zbynek]

Split from #10261 (see comments in that PR for discussion).

Fixes #10278

[zbynek]

Stats for GeoGebra main chunk

before:
pretty:21671810
obfuscated:7864283
gzipped:2554348

after:
pretty:21670169
obfuscated:7863399
gzipped:2553679

So this seems to be just .03% improvement.

[niloc132]

So this seems to be just .03% improvement.

Right, most of these are going to be tiny on their own, or will depend on the specific code being compiled repeating this pattern.

I still think changes like this in pattern matching simple code is worth it - we're adding a single if in an edge case, and DCE is specifically designed to converge in a single pass (though other optimizations can interact with it and require another later pass). The theory is that if we find other code later that can be rewritten trivially to false/true, we will get to propagate that out and clean up other code - and now that will even work if the boolean is trapped in a multiexpr.