JS: support internal visibility from friend modules

Friend modules should be provided using the -Xfriend-modules flag
in the same format as -libraries. No manual configuration required for
JPS, Gradle and Maven plugins.

Friend modules could be switched off using the -Xfriend-modules-disabled
flag. Doing that will
  * prevent internal declarations from being exported,
  * values provided by -Xfriend-modules ignored,
  * raise a compilation error on attemps to use internal declarations from other modules

Fixes #KT-15135 and #KT-16568.

js/js.translator/testData/box/jsName/peculiarIdentifiers.kt

@@ -14,9 +14,11 @@ fun test2(`p 1`: Int, `.p 2`: Int) = `+`(`p 1`, `.p 2`)
 fun test3(): String {
     val `#` = "K"
     class ` `(private val `::`: String) {
-        internal fun `@`() = `::` + `#`
+        private fun `@`() = `::` + `#`
+
+        operator fun invoke() = `@`()
     }
-    return ` `("O").`@`()
+    return ` `("O")()
 }
 
 fun test4(): String {