Fix AssertionError in CodegenUtil.getDelegates

Change getAllOverriddenDescriptors contracti, now it returns
original (not substituted) descriptors without any duplicates.

First of all it's necessary in CodegenUtil.getDelegates to avoid
duplicates (see assertion there), but also it's convenient for all
other usages of this method

 #KT-8154 Fixed

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

@@ -5748,6 +5748,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("kt8154.kt")
+            public void testKt8154() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/delegation/kt8154.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("compiler/testData/diagnostics/tests/delegation/clashes")
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -5655,6 +5655,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/delegation/delegationToVal.kt");
             doTest(fileName);
         }
+
+        @TestMetadata("kt8154.kt")
+        public void testKt8154() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/delegation/kt8154.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/destructuringDeclInLambdaParam")