libsframe: testsuite: make test names unique

libsframe: testsuite: make test names unique

Fix PR libsframe/33437 - libsframe test names are not unique

The TEST () macro definition originally in plt-findfre-2.c, was being
used to differentiate between multiple runs of the testcases.  Adapt
that definition a bit to allow for a variable number of arguments following
the test condition: A test name format string may be used by macro
users, such that the name of the tests are unique.

Move the new variadic TEST macro definition in the testsuite's common
header sframe-test.h, and use it throughout the testsuite.

Reviewed-by: Jens Remus <jremus@linux.ibm.com>
libsframe/testsuite/
	PR libsframe/33437
	* libsframe.decode/be-flipping.c: Use new TEST macro with
	suffix.
	* libsframe.decode/frecnt-1.c: Likewise.
	* libsframe.decode/frecnt-2.c: Likewise.
	* libsframe.encode/encode-1.c: Likewise.
	* libsframe.find/findfre-1.c: Likewise.
	* libsframe.find/findfunc-1.c: Likewise.
	* libsframe.find/plt-findfre-1.c: Likewise.
	* libsframe.find/plt-findfre-2.c: Likewise.
	* sframe-test.h: Move the TEST macro definition to this
	testsuite header.