[IR] Support user-defined equals for MFVC

Signed-off-by: Evgeniy.Zhelenskiy <Evgeniy.Zhelenskiy@jetbrains.com>

#KT-1179

compiler/testData/codegen/box/valueClasses/mfvcBothEqualsOverride.kt

@@ -0,0 +1,53 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// https://youtrack.jetbrains.com/issue/KT-52236/Different-modality-in-psi-and-fir
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +CustomEqualsInValueClasses
+// TARGET_BACKEND: JVM_IR
+// CHECK_BYTECODE_LISTING
+
+var counter = 0
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class MFVC(val x: Int, val y: Int) {
+
+    fun equals(other: MFVC): Boolean {
+        counter++
+        return x == other.x && this.y == other.y
+    }
+
+    override fun equals(other: Any?): Boolean {
+        counter++
+        if (other !is MFVC) {
+            return false
+        }
+        return equals(other)
+    }
+
+    override fun hashCode(): Int {
+        counter++
+        return x + 13 * y
+    }
+}
+
+fun box(): String {
+    val mfvc1 = MFVC(1, 2)
+    val mfvc2 = MFVC(3, 4)
+    
+    require(mfvc1.equals(mfvc1))
+    require(!mfvc1.equals(mfvc2))
+    require(!mfvc2.equals(mfvc1))
+    require(mfvc2.equals(mfvc2))
+    
+    require(mfvc1.equals(mfvc1 as Any?))
+    require(!mfvc1.equals(mfvc2 as Any?))
+    require(!mfvc2.equals(mfvc1 as Any?))
+    require(mfvc2.equals(mfvc2 as Any?))
+    
+    require(mfvc1.hashCode() == 27)
+    require(mfvc2.hashCode() == 55)
+    
+    require(counter == 4 + 2 * 4 + 2)
+    
+    return "OK"
+}