[RISCV] Expand PseudoTAIL with t2 instead of t1 for Zicfilp. (#89014)

PseudoTail should be a software guarded branch in Ziciflp, since its
branch target is known in link time. JALR/C.JR/C.JALR with rs1 as t2 is
termed a software guarded branch. Such branches do not need to land on a
lpad instruction.

ABI Change PR: https://github.com/riscv-non-isa/riscv-asm-manual/pull/93