[Mips][AMDGPU] Update test cases to not use vector lt/gt compares that can be...

[Mips][AMDGPU] Update test cases to not use vector lt/gt compares that can be simplified to an equality/inequality or to always true/false.

For example 'ugt X, 0' can be simplified to 'ne X, 0'. Or 'uge X, 0' is always true.

We already simplify this for scalars in SimplifySetCC, but we don't currently for vectors in SimplifySetCC. D42948 proposes to change that.

llvm-svn: 324436