[WebAssembly] Fix operand rewriting in inline asm lowering.

Use MachineOperand::ChangeToImmediate rather than reassigning
MachineOperands to new values created from MachineOperand::CreateImm,
so that their parent pointers are preserved.

This fixes "Instruction has operand with wrong parent set" errors
reported by the MachineVerifier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341389 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed