JS: support SAM conversion

The SAM adapter is generate on declaration site. This is different
from the JVM approach.

`external fun interface` is banned for now.

Reusing interface declaration for the adapter is a hack which
reduces code size and makes importing/exporting the adapter
effortless.

compiler/testData/codegen/box/funInterface/funInterfaceInheritance.kt

@@ -0,0 +1,33 @@
+// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+// IGNORE_BACKEND: JVM, JVM_IR, JS_IR
+// IGNORE_BACKEND_FIR: JVM_IR
+// SKIP_DCE_DRIVEN
+
+fun interface Base {
+    fun doStuff(): String
+}
+
+fun interface I : Base
+
+fun interface Proxy : I {
+
+    override fun doStuff(): String = doStuffInt().toString()
+
+    fun doStuffInt(): Int
+}
+
+fun runBase(b: Base) = b.doStuff()
+
+fun runI(i: I) = i.doStuff()
+
+fun runProxy(p: Proxy) = p.doStuff()
+
+fun box(): String {
+
+    if (runI { "i" } != "i") return "fail1"
+
+    if (runProxy { 10 } != "10") return "fail2"
+
+    return runBase { "OK" }
+}