[RISCV] Add test cases for missed opportunities to use sbsetw/sbclrw/sbinvw...

[RISCV] Add test cases for missed opportunities to use sbsetw/sbclrw/sbinvw when the result isn't known to be sign extended.

If the input isn't sign extended, but the output of the or/xor/and
is used by a sign_inreg we can still use sbsetw/sbclrw/sbinvw.