[Wasm] Add @JsExport diagnostics test

@JsExport is only allowed on top-level functions in K/Wasm

Restrictions for nested function are handled by reusing K/JS diagnostics
Restrictions for classes and properties are handled by specifying
 annotation target in stdlib

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/diagnostics/DiagnosticsWasmTestGenerated.java

@@ -50,5 +50,11 @@ public class DiagnosticsWasmTestGenerated extends AbstractDiagnosticsWasmTest {
         public void testInheritance() throws Exception {
             runTest("compiler/testData/diagnostics/wasmTests/jsInterop/inheritance.kt");
         }
+
+        @Test
+        @TestMetadata("jsExport.kt")
+        public void testJsExport() throws Exception {
+            runTest("compiler/testData/diagnostics/wasmTests/jsInterop/jsExport.kt");
+        }
     }
 }