Fix mutable collection stub methods generation for corner case

The problem is that
`override fun remove(element: E): CollectionWithRemove<E>`
seems to be illegal from Java's point of view, while it's OK for JVM

These declarations have the same signature (return type is isgnored)
- override fun remove(element: E): CollectionWithRemove<E>
- override fun remove(element: E): Boolean

When we meet such declaration we choose random declaration for fake override in synthetic class
that may lead to signature clash

compiler/testData/codegen/bytecodeListing/immutableCollection.kt

@@ -0,0 +1,30 @@
+interface ImmutableCollection<out E> : Collection<E> {
+    fun add(element: @UnsafeVariance E): ImmutableCollection<E>
+    fun addAll(elements: Collection<@UnsafeVariance E>): ImmutableCollection<E>
+    fun remove(element: @UnsafeVariance E): ImmutableCollection<E>
+}
+
+class ImmutableCollectionmpl<E> : ImmutableCollection<E> {
+    override val size: Int
+        get() = throw UnsupportedOperationException()
+
+    override fun contains(element: E): Boolean {
+        throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun containsAll(elements: Collection<E>): Boolean {
+        throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun isEmpty(): Boolean {
+        throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun iterator(): Iterator<E> {
+        throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun add(element: E): ImmutableCollection<E> = this
+    override fun addAll(elements: Collection<E>): ImmutableCollection<E> = this
+    override fun remove(element: E): ImmutableCollection<E> = this
+}