JS: more default arguments fixes (KT-24413, KT-21968 fixed)

MPP-related:
* inherited from interfaces
* inherited body from interface
* default arguments in an interface, implemented by a class delegate
* super call of a method with default argument

Also:
* inheritance from an interface and another interface descendant (KT-21968)
* inheritance through an intermediate interface

compiler/testData/codegen/box/defaultArguments/function/funInTraitChain.kt

@@ -0,0 +1,20 @@
+// IGNORE_BACKEND: JVM
+// See KT-15971
+
+interface Foo {
+    fun foo(a: Double = 1.0): Double
+}
+
+interface FooChain: Foo
+
+open class Impl {
+    fun foo(a: Double) = a
+}
+
+class FooImpl : FooChain, Impl()
+
+fun box(): String  {
+    if (FooImpl().foo() != 1.0) return "fail"
+    if (FooImpl().foo(2.0) != 2.0) return "fail"
+    return "OK"
+}