KT-4960 Redeclaration is not reported for type parameters of interfaces

When resolving a class body for a class without a primary constructor
(e.g., an interface), no checks were performed for redeclarations
in the corresponding class header.
Creating & initializing a lexical scope of an appropriate kind will do it.
Note that since class has no primary constructor, only type parameters
could be redeclared (and that's KT-4960).

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

@@ -15949,6 +15949,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("interfaceTypeParameters.kt")
+            public void testInterfaceTypeParameters() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/redeclarations/interfaceTypeParameters.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("kt2418.kt")
             public void testKt2418() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/redeclarations/kt2418.kt");