JVM_IR KT-45853 include return type into Java method IdSignature

This is a hack required to accept [potentially] incorrect input
provided by the front-end; see KT-46042.

compiler/testData/codegen/bytecodeListing/kt45853.kt

@@ -0,0 +1,18 @@
+// FILE: kt45853.kt
+open class MyProblem() : ThrowableProblem() {
+    override fun getCause(): Exceptional? = super.cause
+}
+
+// FILE: Exceptional.java
+public interface Exceptional {
+    Exceptional getCause();
+}
+
+// FILE: ThrowableProblem.java
+public abstract class ThrowableProblem extends RuntimeException implements Exceptional  {
+    @Override
+    public ThrowableProblem getCause() {
+        // cast is safe, since the only way to set this is our constructor
+        return (ThrowableProblem) super.getCause();
+    }
+}

compiler/testData/codegen/bytecodeListing/kt45853.txt

@@ -0,0 +1,6 @@
+@kotlin.Metadata
+public class MyProblem {
+    // source: 'kt45853.kt'
+    public method <init>(): void
+    public @org.jetbrains.annotations.Nullable method getCause(): Exceptional
+}

compiler/testData/codegen/bytecodeListing/kt45853a.kt

@@ -0,0 +1,21 @@
+// FILE: kt45853a.kt
+abstract class A {
+    open val a: A? get() = null
+}
+
+class B() : AX() {
+    override fun getA(): X? = super.a
+}
+
+// FILE: X.java
+public interface X {
+    X getA();
+}
+
+// FILE: AX.java
+public abstract class AX extends A implements X {
+    @Override
+    public AX getA() {
+        return (AX) super.getA();
+    }
+}

compiler/testData/codegen/bytecodeListing/kt45853a.txt

@@ -0,0 +1,13 @@
+@kotlin.Metadata
+public abstract class A {
+    // source: 'kt45853a.kt'
+    public method <init>(): void
+    public @org.jetbrains.annotations.Nullable method getA(): A
+}
+
+@kotlin.Metadata
+public final class B {
+    // source: 'kt45853a.kt'
+    public method <init>(): void
+    public @org.jetbrains.annotations.Nullable method getA(): X
+}