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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/errorResistance/propertyInitializer.kt

@@ -0,0 +1,7 @@
+// WITH_STDLIB
+
+import broken.lib.Foo
+
+val x = run {
+    Foo("foo", 1).result
+}