Reorganized SAM-related test data.

compiler/testData/codegen/box/samConstructors/syntheticVsReal.kt

@@ -0,0 +1,12 @@
+var global = ""
+
+fun Runnable(f: () -> Unit) = object : Runnable {
+    public override fun run() {
+        global = "OK"
+    }
+}
+
+fun box(): String {
+    Runnable { global = "FAIL" } .run()
+    return global
+}