public int getDepth() {
		return getProgram().getParentDepth(getHeadFragment().getIndex());
	}
Returns the depth of the head fragment, where depth is defined as
the distance between the DIE and the root DIE of the owning compilation
unit.
<p>
The root die would return 0, the children of the root will return 1, etc.
<p>
This value matches the nesting value shown when dumping DWARF
info using 'readelf'.

@return depth of this instance, from the root of its head DIE fragment, with 0 indicating
that this instance was already the root of the compUnit
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/DIEAggregate.java