run-tests: Stop explicitly linking against -lssp for the fortification test

Since libmingwex.a provides these routines now, we don't need to
specify -lssp manually.

test/Makefile

@@ -174,7 +174,7 @@ $(TARGETS_CFGUARD): %$(EXEEXT): %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $< -o $@ -mguard=cf
 
 $(TARGETS_FORTIFY): %-fortify$(EXEEXT): %.c
-	$(CC) $(CPPFLAGS) $(CFLAGS) $< -o $@ -O2 -D_FORTIFY_SOURCE=2 -lssp
+	$(CC) $(CPPFLAGS) $(CFLAGS) $< -o $@ -O2 -D_FORTIFY_SOURCE=2
 
 $(TARGETS_ASAN): %-asan$(EXEEXT): %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $< -o $@ -fsanitize=address -g -gcodeview -Wl,--pdb=