Supress warnings emitted during Wasm and JS tests compilation

- Opted into ExperimentalWasmJsInterop
- Supressed a "cast will always fail" warning


Merge-request: KT-MR-23830
Merged-by: Filipp Zhinkin <[email protected]>

Author: fzhinkin

libraries/kotlin.test/wasm/js/src/test/kotlin/AdapterTransformerTest.kt

@@ -7,6 +7,7 @@ package kotlin.test.tests
 
 import kotlin.test.*
 
+@OptIn(ExperimentalWasmJsInterop::class)
 private fun wrapAdapter(externalAdapter: ExternalFrameworkAdapter): ExternalFrameworkAdapter = js("""{
     return {
         suite: (name, ignored, suiteFn) => externalAdapter.suite(name, ignored, suiteFn),
@@ -20,6 +21,7 @@ private class TestAdapter : FrameworkAdapter {
     override fun test(name: String, ignored: Boolean, testFn: () -> Any?) { testResult = testFn() }
 }
 
+@OptIn(ExperimentalWasmJsInterop::class)
 class AdapterTransformerTest {
     @Test
     fun loopAround() {

libraries/kotlin.test/wasm/js/src/test/kotlin/AsyncTest.kt

@@ -10,6 +10,7 @@ import kotlin.test.*
 
 private external fun setTimeout(body: () -> Unit, timeout: Int)
 
+@OptIn(ExperimentalWasmJsInterop::class)
 class AsyncTest {
 
     var log = ""
@@ -58,6 +59,7 @@ class AsyncTest {
 
     @Test
     fun checkCustomPromise(): CustomPromise {
+        @Suppress("CAST_NEVER_SUCCEEDS")
         return promise(10, "") as CustomPromise
     }