[Mips] Supplement long branch pseudo instructions

Expand on LONG_BRANCH_LUi and LONG_BRANCH_(D)ADDiu pseudo
instructions by creating variants which support
less operands/accept GPR64Opnds as their operand in order
to appease the machine verifier pass.

Differential Revision: https://reviews.llvm.org/D53977

llvm-svn: 346133