[LL FIR] rename testdata to testData to avoid copyright generation

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/fileStructure/localPropertyScript.kts

@@ -0,0 +1,15 @@
+/* RootScriptStructureElement */fun foo() {/* DeclarationStructureElement */
+    var x: Int
+}
+class A {/* ClassDeclarationStructureElement */
+    fun q() {/* DeclarationStructureElement */
+        val y = 42
+    }
+}
+class B {/* ClassDeclarationStructureElement */
+    class C {/* ClassDeclarationStructureElement */
+        fun u() {/* DeclarationStructureElement */
+            var z: Int = 15
+        }
+    }
+}