Add the "test-force" target to "Makefile.am".

Makefile.am:
  Add the "test-force" target, because we use it in RPM building.
  (Backport of Monty's fix from 5.0)

Makefile.am

@@ -100,4 +100,10 @@ tags:
 # Test installation
 
 test:
-	cd mysql-test; perl mysql-test-run.pl && perl mysql-test-run.pl --ps-protocol
+	cd mysql-test; \
+	perl ./mysql-test-run && perl ./mysql-test-run --ps-protocol
+
+test-force:
+	cd mysql-test; \
+	./mysql-test-run --force ;\
+	./mysql-test-run --ps-protocol --force