testsuite: Require gas in gcc.dg/hierarchical-discriminator-loop-version.c etc. scans

testsuite: Require gas in gcc.dg/hierarchical-discriminator-loop-version.c etc. scans

The gcc.dg/hierarchical-discriminator-loop-version.c etc. tests FAIL on
Solaris with the native assembler:

FAIL: gcc.dg/hierarchical-discriminator-loop-version.c scan-assembler \\\\.loc 1 (9|10) [0-9]+ is_stmt 0 discriminator [0-9]+
FAIL: gcc.dg/hierarchical-discriminator-unroll.c scan-assembler \\\\.loc 1 17 7 is_stmt 0 discriminator ([1-9][0-9]*|0x[1-9a-fA-F][0-9a-fA-F]*)
FAIL: gcc.dg/hierarchical-discriminator-vect-version.c scan-assembler \\\\.loc 1 13 [0-9]+ is_stmt 0 discriminator ([1-9][0-9]*|0x[1-9a-fA-F][0-9a-fA-F]*)

When using Solaris as, the .loc directives aren't present.  Their use is
guarded by dwarf2out.cc (dwarf2out_default_as_loc_support), which
ultimately depends on HAVE_AS_DWARF2_DEBUG_LINE

To avoid this, this patch restricts the scans to gas targets, which is
better than what we currently have.

Tested on i386-pc-solaris2.11 and sparc-sun-solaris2.11 (as and gas),
and x86_64-pc-linux-gnu.

2026-02-17  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	* gcc.dg/hierarchical-discriminator-loop-version.c
	(scan-assembler): Require gas.
	* gcc.dg/hierarchical-discriminator-unroll.c: Likewise.
	* gcc.dg/hierarchical-discriminator-vect-version.c: Likewise.