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

We exclude testData pattern from copyright scope

analysis/low-level-api-fir/testData/lazyResolve/fakeOverrideScript.kts

@@ -0,0 +1,18 @@
+fun ex<caret>pression(expression: IrConst<*>) {
+    when (val kind = expression.kind) {
+        is Kind.Null -> kind.valueOf(expression)
+        else -> {}
+    }
+}
+
+sealed class Kind<T>(val asString: String) {
+    @Suppress("UNCHECKED_CAST")
+    fun valueOf(aConst: IrConst<*>) = (aConst as IrConst<T>).value
+    object Null : Kind<Nothing?>("Null")
+    override fun toString() = asString
+}
+
+abstract class IrConst<T> {
+    abstract var kind: Kind<T>
+    abstract var value: T
+}