K2: prefer derived class sources for callable copies (e.g. fake overrides)

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/accidentalOverrides/delegatedFunctionOverriddenByProperty.fir.kt

@@ -1,9 +0,0 @@
-interface B {
-    fun getX() = 1
-}
-
-interface D {
-    <!ACCIDENTAL_OVERRIDE!>val x: Int<!>
-}
-
-class C(d: D) : D by d, B

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/accidentalOverrides/delegatedFunctionOverriddenByProperty.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface B {
     fun getX() = 1
 }