JS: fix translation of extension properties

js/js.translator/testData/box/extensionProperty/externalExtensionProperty.kt

@@ -0,0 +1,14 @@
+// MODULE: lib
+// FILE: lib.kt
+
+class A {
+    fun ok() = "OK"
+}
+
+val A.foo: String
+    get() = ok()
+
+// MODULE: main(lib)
+// FILE: main.kt
+
+fun box() = A().foo

js/js.translator/testData/box/extensionProperty/privateExtensionProperty.kt

@@ -0,0 +1,8 @@
+class A {
+    fun result() = "OK"
+}
+
+private val A.foo: String
+    get() = result()
+
+fun box() = A().foo