[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/insideLoop.kt

@@ -0,0 +1,14 @@
+interface Node {
+    val parent: Node?
+}
+
+fun test(initial: Node) { 
+    var current = initial
+    
+    while (current != null) {
+        <expr>consume(current)</expr>
+        current = current.parent
+    }
+}
+
+fun consume(node: Node) {}