[FIR JS] Prepare the test data for FIR

compiler/testData/diagnostics/testsWithJsStdLib/native/overrideOptionalParam.fir.kt

@@ -0,0 +1,60 @@
+open external class A {
+    open fun f(x: Int = definedExternally)
+}
+
+class B : A() {
+    override fun f(x: Int) {}
+}
+
+class BB : A()
+
+external class C : A {
+    override fun f(x: Int)
+}
+
+
+external interface I {
+    fun f(x: Int = definedExternally)
+}
+
+interface J {
+    fun f(x: Int = 23)
+}
+
+interface II {
+    fun f(x: Int)
+}
+
+interface IIJ : II, J
+
+open external class D {
+    open fun f(x: Int)
+}
+
+class E : D() {
+    override fun f(x: Int) { }
+}
+
+class F : D(), I {
+    override fun f(x: Int) {}
+}
+
+external class G : D, I {
+    override fun f(x: Int)
+}
+
+open class X {
+    fun f(x: Int) {}
+}
+
+open external class XE {
+    fun f(x: Int)
+}
+
+class Y : X(), I
+
+class YY : A(), II
+
+external class YE: XE, I
+
+class Z : X(), J