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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/getOrBuildFir/declarations/whereClause2Script.kts

@@ -0,0 +1,3 @@
+// WITH_STDLIB
+fun <From, To> copyNotNull(from: List<From>, to: List<To>) where From : To, <expr>To</expr> : Any {
+}