Expressions.JS: Bitwise left shift bugfixes, #1034

[paulirwin]

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Mask off 63 from shift operand to prevent overflow on x86, and cast to 32-bit operand.

Fixes #1034

Description

On x86 .NET Framework, the ANTLR/IL changes in #996 behave differently than other platforms. This seems to be due to x86 .NET Framework not masking off the operand correctly. Other platforms mask this off by 0x3f (63) since shifting by 64 or more would overflow, so this basically wraps the shift instead of overflowing. x86 netfx for some reason does not do this correctly. This adds a mask that does no harm on other platforms, but ensures that all are operating the same way.

Additionally, to fix an issue on .NET 5/6 (still usable with our netstandard2.1 target), the right operand must be an Int32 in case it overflows. If the operand is an Int64 and it is out of range, it can crash the process as an invalid program.

Note that this inlines the CompileBinary logic and no longer uses that method because we want to only mask off the second operand, not the first.

[NightOwl888]

Thanks for the PR.

I ran the tests 8x on Azure Devops and there were no x86 test failures. There was a new failing test found, but it was unrelated to this change (it also fails on master). See: #1050.