Use "Any?" as out-type for type parameters instead of intersection of bounds

Also refactor checkSubtypeForTheSameConstructor to compute everything in the
best order

compiler/testData/diagnostics/tests/subtyping/invariantArgumentForTypeParameterWithMultipleBounds.kt

@@ -0,0 +1,18 @@
+import java.io.Serializable
+
+class A<T> where T : Cloneable, T : Serializable
+
+interface CS1 : Cloneable, Serializable
+interface CS2 : CS1
+
+interface I1 {
+    fun foo(): A<in CS2>
+}
+
+interface I2 : I1 {
+    override fun foo(): A<CS1>
+}
+
+interface I3 : I1 {
+    override fun foo(): A<in CS1>
+}

compiler/testData/diagnostics/tests/subtyping/invariantArgumentForTypeParameterWithMultipleBounds.txt

@@ -0,0 +1,43 @@
+package
+
+public final class A</*0*/ T : kotlin.Cloneable> where T : java.io.Serializable {
+    public constructor A</*0*/ T : kotlin.Cloneable>() where T : java.io.Serializable
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface CS1 : kotlin.Cloneable, java.io.Serializable {
+    protected open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface CS2 : CS1 {
+    protected open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface I1 {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): A<in CS2>
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface I2 : I1 {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ fun foo(): A<CS1>
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface I3 : I1 {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ fun foo(): A<in CS1>
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}