gas: avoid spurious failures in non-ELF targets in the SPARC testsuite.

gas: avoid spurious failures in non-ELF targets in the SPARC testsuite.

Many of the existing sparc tests fail in non-ELF targets (coff and
a.out) due to spurious differences in the expected results:

- Unlike ELF, a.out text sections are aligned to 2**3 and padded
  accordingly.  The padding instruction is a `nop' (01 00 00 00).

- Likewise, coff text sections are also aligned to 2**3 and padded
  accordingly.  However, the padding instruction in these targets is an
  `illtrap 0' (00 00 00 00).

- Unlike ELF, a.out and coff binaries don't contain hardware
  capabilities bits that could be used by BFD to determine the opcodes
  architecture corresponding to the instructions encoded in the
  objects (v9, v9a, v9b, v9c, etc).  Consequently, in both a.out and
  coff tests we would need to pass proper `-m sparc:vXXX' options when
  invoking objdump before comparing results.

In order to fix these issues, the most obvious solution would be to have
three variants of .d files per impacted test.  For example, for save.d
we would have: save-elf.d, save-aout.d and save-coff.d.  Using the
`#source' directive, a single save.s file would provide the input for
all of them.  However, this approach has the following problems:

- The #target and #notarget .d directives are very limited: they use
  globs instead of regular expressions, and thus it is not possible (or
  too messy) to use them to discriminate between elf, coff and a.out
  sparc targets.

- It adds little or no value to have variants of all these tests for all
  the target types, and it would be a burden to maintain them.  Actually
  the features tested in the spuriously failing tests (relatively modern
  sparc instructions, registers and asis) are not really found in
  running coff or a.out sparc systems.

This patch changes sparc.exp so it will run these tests only in
ELF-targets, using the more standard `is_elf_format' from
binutils-common.exp instead of the ad-hoc (and less convenient, as it
must be called before _every_ single elf-only test) sparc_elf_setup.

Incidentally, the patch also fixes the #name entry for save-args.d.

Tested in sparc*-*-linux-gnu, sparc-aout and sparc-coff targets.

gas/ChangeLog:

2016-07-27  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* testsuite/gas/sparc/sparc.exp: Use is_elf_format to discriminate
	ELF targets.
	Run natural, natural-32, pr4587, ticc-imm-reg, v8-movwr-imm,
	pause, save-args, cbcond, cfr, crypto edge, flush, hpcvis3, ima,
	ld_st_fsr, ldtw_sttw, ldd_std, ldx_stx, ldx_efsr, mwait, mcdper,
	sparc5vis4, xcrypto, v9branch1 and imm-plus-rreg only in ELF
	targets.
	(sparc_elf_setup): Delete.
	* testsuite/gas/sparc/save-args.d: Fix a copy-paste typo in the
	test's #name entry.