Fix for a bug that caused invalid code generated for calling extension from another extension.

js/js.translator/testFiles/extensionFunction/cases/implicitReceiverInExtension.kt

@@ -0,0 +1,7 @@
+package foo
+
+fun <T> T.toPrefixedString(prefix: String = "", suffix: String="") = prefix + toString() + suffix
+
+fun box() : Boolean {
+    return ("mama".toPrefixedString(suffix="321", prefix="papa") == "papamama321")
+}