Revert "JIT: Use rsb and shift in easy multiply."

This reverts commit d37cc8e2299393e4a018e751075028d452be06ae.

Conflicts:
	vm/compiler/codegen/arm/ArmLIR.h
	vm/compiler/codegen/arm/Assemble.cpp
	vm/compiler/codegen/arm/Thumb/Gen.cpp
	vm/compiler/codegen/arm/Thumb2/Gen.cpp