testsuite: Disable zero-scratch-regs-{8, 9, 10, 11}.c on all but ... [PR97680]

testsuite: Disable zero-scratch-regs-{8, 9, 10, 11}.c on all but ... [PR97680]

Seems the target hook is only defined on
config/i386/i386.c:#undef TARGET_ZERO_CALL_USED_REGS
config/i386/i386.c:#define TARGET_ZERO_CALL_USED_REGS ix86_zero_call_used_regs
config/sparc/sparc.c:#undef TARGET_ZERO_CALL_USED_REGS
config/sparc/sparc.c:#define TARGET_ZERO_CALL_USED_REGS sparc_zero_call_used_regs
but apparently many of the tests actually succeed on various targets that
don't define those hooks.  E.g. I haven't seen them to fail on aarch64,
on arm only the -10.c fails, on powerpc*/s390* all {8,9,10,11} fail (plus
5 is skipped on power*-aix*).
On ia64 according to testresults {6,7,8,9,10,11} fail, some with ICEs.
On mipsel according to testresults {9,10,11} fail, some with ICEs.
On nvptx at least 1-9 succeed, 10-11 don't know, don't have assert.h around.

I've kept {5,6,7} with aix,ia64,ia64 skipped because those seems like
outliers, it works pretty much everywhere but on those.
The rest have known good targets.

2021-03-31  Jakub Jelinek  <jakub@redhat.com>

	PR testsuite/97680
	* c-c++-common/zero-scratch-regs-6.c: Skip on ia64.
	* c-c++-common/zero-scratch-regs-7.c: Likewise.
	* c-c++-common/zero-scratch-regs-8.c: Change from dg-skip-if of
	selected unsupported triplets to all targets but selected triplets
	of supported targets.
	* c-c++-common/zero-scratch-regs-9.c: Likewise.
	* c-c++-common/zero-scratch-regs-10.c: Likewise.
	* c-c++-common/zero-scratch-regs-11.c: Likewise.