test suite update - gdb.base/[ab]

test suite update - gdb.base/[ab]

Convert files gdb.base/[ab]*.exp to use standard_output_file et al.

	* a2-run.exp, all-bin.exp, annota1.exp, annota3.exp, anon.exp,
	args.exp, arithmet.exp, arrayidx.exp, assign.exp, async-shell.exp,
	async.exp, attach-pie-misread.exp, attach-pie-noexec.exp,
	attach-twice.exp, attach.exp, auxv.exp, bang.exp, bfp-test.exp,
	bigcore.exp, bitfields.exp, bitfields2.exp, break-entry.exp,
	break-interp.exp, break-on-linker-gcd-function.exp,
	breakpoint-shadow.exp: Use standard_testfile,
	standard_output_file, prepare_for_testing, clean_restart.