binutils testsuite: replace unresolved with unsupported

binutils testsuite: replace unresolved with unsupported

You'd think "unresolved" would be correct for an objcopy test when the
assembler refuses to assemble one of our source files.  After all, the
test of objcopy hasn't been run.  However, "unresolved" results in
runtest returning with an error status.  If instead we report
"unsupported", runtest returns success.  Which is a little less
confusing to a user who doesn't see any errors reported unless they
look in log files.

	* testsuite/binutils-all/objcopy.exp: Report "unsupported" when
	gas or ld fails to build a testcase rather than "unresolved".
	Report "fail" when readelf returns an error status rather than
	"unresolved".
	* testsuite/binutils-all/ar.exp: Likewise.
	* testsuite/binutils-all/compress.exp: Likewise.
	* testsuite/binutils-all/readelf.exp: Likewise.