[OpenGOAL] make multiplication/divsion like GOAL and support in decompiler

[water111]

This makes power-of-two multiplies and divides optimized to shifts work correctly in the compiler/decompiler.

There is a possibility of false detection. The behavior will still be correct, but there might be a multiply/divide when the original code had a shift.

The decompiler uses these rules to pick between shifting and multiply/divide.

• bitfield access always wins over a multiply or divide. Accessing bitfields will not be affected by this change.
• Large shifts (over 10, or multiply/divide by 1024) are not converted to multiplication or division.
• Unsigned divides (logical shift) are never converted to division. Too many false positives and GOAL programmers didn't use uint types very often.

This also adds the same optimization to OpenGOAL and implements unsigned division. Previously it just did signed division every time.

[coveralls]

Pull Request Test Coverage Report for Build 843605553

• 121 of 149 (81.21%) changed or added relevant lines in 10 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.01%) to 69.213%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/util/BitUtils.h	8	9	88.89%
decompiler/IR2/FormExpressionAnalysis.cpp	36	42	85.71%
decompiler/IR2/bitfields.cpp	17	38	44.74%

Files with Coverage Reduction	New Missed Lines	%
decompiler/IR2/FormExpressionAnalysis.cpp	1	80.72%
decompiler/IR2/Form.cpp	2	73.99%

Totals
Change from base Build 843069498:	0.01%
Covered Lines:	34469
Relevant Lines:	49801

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💛 - Coveralls