This avoids completing types for DINFO_LEVEL_TERSE by using
the should_emit_struct_debug machinery.

2020-03-27  Richard Biener  <rguenther@suse.de>

	PR debug/94273
	* dwarf2out.c (should_emit_struct_debug): Return false for
	DINFO_LEVEL_TERSE.

	* g++.dg/debug/pr94273.C: New testcase.