Add test for generic setValue called via synthetic accessor

Synthetic accessor for 'setValue' was generated incorrectly,
specific case of KT-20491 (Incorrect synthetic accessor generated for a
generic base class function specialized with primitive type).

Make sure there's no equivalent of KT-20387 for delegated properties.

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -7619,6 +7619,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
         }
 
+        @TestMetadata("genericSetValueViaSyntheticAccessor.kt")
+        public void testGenericSetValueViaSyntheticAccessor() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/delegatedProperty/genericSetValueViaSyntheticAccessor.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("getAsExtensionFun.kt")
         public void testGetAsExtensionFun() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/delegatedProperty/getAsExtensionFun.kt");