Check for the presence of dispatch receiver too in isEqualsDescriptor()

Otherwise, top-level function with the name 'equals' and suitable
signature will be (erroneously) treated as true 'equals' invocation,
leading to further exception (see EA-126602)

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -14501,6 +14501,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/override/ExtendFunctionClass.kt");
             }
 
+            @TestMetadata("fakeEquals.kt")
+            public void testFakeEquals() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/fakeEquals.kt");
+            }
+
             @TestMetadata("FakeOverrideAbstractAndNonAbstractFun.kt")
             public void testFakeOverrideAbstractAndNonAbstractFun() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/override/FakeOverrideAbstractAndNonAbstractFun.kt");