Duplicate tests that are run twice as both C and C++ tests to fix parallel make: overload_extend

Examples/test-suite/schemerunme/overload_extend_c.scm

@@ -0,0 +1,12 @@
+(define f (new-Foo))
+
+(if (not (= (Foo-test f 3) 1))
+    (error "test integer bad"))
+
+(if (not (= (Foo-test f "hello") 2))
+    (error "test string bad"))
+
+(if (not (= (Foo-test f 3.5 2.5) 6.0))
+    (error "test reals bad"))
+
+(exit 0)