Commit ccb9eba6 updated the testsuite for some targets without
running the testsuite on those targets.  This patch corrects the
update, in most cases just adding the expected full-stop.

On powerpc64le-linux, fixes these:
FAIL: gdb.arch/powerpc-d128-regs.exp: checking for PPC arch
FAIL: gdb.arch/powerpc-disassembler-options.exp: set architecture powerpc:common64
FAIL: gdb.arch/powerpc-disassembler-options.exp: set architecture rs6000:6000
FAIL: gdb.arch/ppc64-symtab-cordic.exp: show architecture

I also verified that arm-linuxeabi and s390x-linux cross-builds now
pass their disassembler-options.exp tests.

	* gdb.arch/arm-disassembler-options.exp: Adjust expected
	"target architecture" output.
	* gdb.arch/powerpc-d128-regs.exp: Likewise.
	* gdb.arch/powerpc-disassembler-options.exp: Likewise.
	* gdb.arch/ppc64-symtab-cordic.exp: Likewise.
	* gdb.arch/s390-disassembler-options.exp: Likewise.