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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/contextCollector/smartCasts/dispatchReceiver.kt

@@ -0,0 +1,11 @@
+open class Foo {
+    fun foo() {
+        if (this is Bar) {
+            <expr>consume(this)</expr>
+        }
+    }
+}
+
+class Bar : Foo()
+
+fun consume(obj: Bar) {}