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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/fileStructure/localUnitFunction.lazy.resolve.txt

@@ -0,0 +1,7 @@
+FILE: [ResolvedTo(BODY_RESOLVE)] localUnitFunction.kt
+    public final [ResolvedTo(BODY_RESOLVE)] fun foo(): R|kotlin/Unit| {
+        local final [ResolvedTo(BODY_RESOLVE)] fun local(): R|kotlin/Unit| {
+            <Unresolved name: println>#(String(local))
+        }
+
+    }