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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/contextCollector/file.kt

@@ -0,0 +1,15 @@
+package <expr>test</expr>
+
+import java.util.List
+
+fun test() = List::class
+
+fun other(): Int {
+    return "foo".length
+}
+
+class Foo {
+    fun foo() {
+        require(other() == 3)
+    }
+}