tests/include: Move EMPTY_WRAP() macro to tests/include/test.h

EMPTY_WRAP() might be useful for tests other than CBFS's ones. Move it
to the main tests header file to make it easily accessible.

Change-Id: Ic06c55912488681daf6d2c48cb0c879fa97ba4be
Signed-off-by: Jakub Czapiga <jacz@semihalf.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60971
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>

tests/include/tests/test.h

@@ -14,6 +14,9 @@
 #include <setjmp.h>
 #include <cmocka.h>
 
+/* This macro basically does nothing but suppresses linter messages */
+#define EMPTY_WRAP(...) __VA_ARGS__
+
 /*
  * Set symbol value and make it global.
  */