[modules] Fix a rejects-valid resulting from emitting an inline function
recursively within the emission of another inline function. This ultimately
led to us emitting the same inline function definition twice, which we then
rejected because we believed we had a mangled name conflict.
[Cleanup] Utility function to erase instruction and mark DBG_Values

New function to erase a machine instruction and mark DBG_VALUE
for removal. A DBG_VALUE is marked for removal when it references
an operand defined in the instruction.
Use the new function to cleanup code in dead machine instruction
removal pass.