[RISCV][GISel] Add ISel supports for SHXADD from Zba extension (#67863)

This patch consists of porting SDISel patterns of SHXADD instructions to
GISel.
Note that `non_imm12`, a predicate that was implemented with `PatLeaf`,
is now turned into a `PatFrag` of `<op>_with_non_imm12` where `op` is
the operator that uses `the non_imm12` operand, as GISel doesn't have
equivalence of `PatLeaf` at this moment.