[DebugInfo] Handle generic type DW_OP_convert ops in llvm-dwarfdump
This is a preparatory change for allowing LLVM to emit DW_OP_convert
operations converting to the generic type.
If DW_OP_convert's operand is 0, it converts the top of stack to the
generic type, as specified by DWARFv5 section 22.214.171.124:
"[...] takes one operand, which is an unsigned LEB128 integer that
represents the offset of a debugging information entry in the current
compilation unit, or value 0 which represents the generic type."
This adds support for such operations to llvm-dwarfdump.
Reviewers: aprantl, markus, jdoerfert, jhenderson
Reviewed By: aprantl
Subscribers: hiraditya, llvm-commits
Tags: debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D76141