MIPS64 TF: Remove kMips64And32, kMips64Or32, kMips64Xor32.

TEST=
BUG=
MIPS64 TF: Fix Word32 unsigned compare operations on HW.

TEST=cctest/test-branch-combine/BranchCombineInt32CmpAllInputShapes_branch_true
BUG=
MIPS64 TF: Fix conversions beetween Uint32/Uint64 and Int32/Int64.

TEST=cctets/test-run-machops/RunChangeUint32ToUint64P
BUG=
MIPS64 TF: Fix loading Float64 constants in turbofan.

TEST=ctest/test-run-machops/RunFloat64SubImm1,
     RunFloat64SubImm2, RunFloat64MulImm, RunFloat64Compare