Drop traits with required classes

#KT-4771 Rejected

compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt

@@ -1,23 +0,0 @@
-package test
-
-abstract class A {
-    abstract fun foo()
-}
-
-interface X : A {
-    fun bar() {
-    }
-}
-
-open class B() : A() {
-    override fun foo() {
-    }
-}
-
-class C() : A(), X {
-    override fun foo() {
-    }
-}
-
-class D(val c: C) : B(), X by c {
-}

compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.txt

@@ -1,30 +0,0 @@
-package test
-
-internal abstract class A {
-    /*primary*/ public constructor A()
-    internal abstract fun foo(): kotlin.Unit
-}
-
-internal open class B : test.A {
-    /*primary*/ public constructor B()
-    internal open override /*1*/ fun foo(): kotlin.Unit
-}
-
-internal final class C : test.A, test.X {
-    /*primary*/ public constructor C()
-    internal open override /*1*/ /*fake_override*/ fun bar(): kotlin.Unit
-    internal open override /*2*/ fun foo(): kotlin.Unit
-}
-
-internal final class D : test.B, test.X {
-    /*primary*/ public constructor D(/*0*/ c: test.C)
-    internal final val c: test.C
-        internal final fun <get-c>(): test.C
-    internal open override /*1*/ /*delegation*/ fun bar(): kotlin.Unit
-    internal open override /*2*/ /*fake_override*/ fun foo(): kotlin.Unit
-}
-
-internal interface X : test.A {
-    internal open fun bar(): kotlin.Unit
-    internal abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
-}