[BOLT][RISCV] Carry-over annotations when fixing calls (#66763)

`FixRISCVCallsPass` changes all different forms of calls to `PseudoCALL`
instructions. However, the original call's annotations were lost in the
process.

This patch fixes this by moving all annotations from the old to the new
call. `MCPlusBuilder::moveAnnotations` had to be made public for this.