[InstCombine] When converting decomposeBitTestICmp's APInt return to...

[InstCombine] When converting decomposeBitTestICmp's APInt return to ConstantInt, make sure we use the type from the Value* that was also returned from decomposeBitTestICmp.

Previously we used the type from the LHS of the compare, but a future patch will change decomposeBitTestICmp to look through truncates so it will return a pretruncated Value* and the type needs to match that.

llvm-svn: 312380