[IR] add JsTextTest for IrScript

compiler/testData/ir/irJsText/scripting/fun.kts

@@ -0,0 +1,13 @@
+fun <T> test1(i: Int, j: T) {}
+
+fun test2(i: Int = 0, j: String = "") {}
+
+fun test3(vararg args: String) {}
+
+fun String.textExt1(i: Int, j: String) {}
+
+class Host {
+    fun String.testMembetExt1(i: Int, j: String) {}
+
+    fun <T> String.testMembetExt2(i: Int, j: T) {}
+}