[MIR] Add comments to INLINEASM immediate flag MachineOperands

Summary:
The INLINEASM MIR instructions use immediate operands to encode the values of some operands.
The MachineInstr pretty printer function already handles those operands and prints human readable annotations instead of the immediates. This patch adds similar annotations to the output of the MIRPrinter, however uses the new MIROperandComment feature.

Reviewers: SjoerdMeijer, arsenm, efriedma

Reviewed By: arsenm

Subscribers: qcolombet, sdardis, jvesely, wdng, nhaehnle, hiraditya, jrtc27, atanasyan, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78088