[RISCV] Support Expressions in .insn Directives (#111893)

When assembling raw instructions, often you want to or together several
fields for clarity, or because you're using an assembly macro with
separate arguments.

This brings the use of `.insn` closer into line with what can be done
with the binutils assembler.

The 64-bit instruction test here explicitly sets the top bit to make
sure this works, even though the assembler is really using `int64_t`
in most places internally.

0 files changed, 0 insertions, 0 deletions