Minor: Fix TODOs in stdlib tests

libraries/stdlib/test/collections/CollectionTest.kt

@@ -483,9 +483,7 @@ class CollectionTest {
 
         val hasNulls = listOf("foo", null, "bar")
 
-        //        TODO replace with more accurate version when KT-5987 will be fixed
-        //        failsWith(javaClass<IllegalArgumentException>()) {
-        assertFails {
+        assertFailsWith<IllegalArgumentException> {
             // should throw an exception as we have a null
             hasNulls.requireNoNulls()
         }

libraries/stdlib/test/text/StringTest.kt

@@ -50,17 +50,14 @@ fun Char.isAsciiUpperCase() = this in 'A'..'Z'
 
 class StringTest {
 
-    // could not be local inside isEmptyAndBlank, because local declarations is not yet supported for JS
-    // TODO: move inside after KT-11030 is implemented
-    class IsEmptyCase(val value: String?, val isNull: Boolean = false, val isEmpty: Boolean = false, val isBlank: Boolean = false)
-
     @test fun isEmptyAndBlank() = withOneCharSequenceArg { arg1 ->
+        class Case(val value: String?, val isNull: Boolean = false, val isEmpty: Boolean = false, val isBlank: Boolean = false)
 
         val cases = listOf(
-            IsEmptyCase(null,              isNull = true),
-            IsEmptyCase("",                isEmpty = true, isBlank = true),
-            IsEmptyCase("  \r\n\t\u00A0",  isBlank = true),
-            IsEmptyCase(" Some ")
+            Case(null,              isNull = true),
+            Case("",                isEmpty = true, isBlank = true),
+            Case("  \r\n\t\u00A0",  isBlank = true),
+            Case(" Some ")
         )
 
         for (case in cases) {

libraries/stdlib/test/utils/TODOTest.kt

@@ -23,7 +23,7 @@ import org.junit.Test as test
 class TODOTest {
     private class PartiallyImplementedClass {
         public val prop: String get() = TODO()
-        //  fun method1() = TODO() as String // <- doesn't compile in JS
+        fun method1() = TODO() as String
         public fun method2(): Int = TODO()
 
         public fun method3(switch: Boolean, value: String): String {
@@ -56,7 +56,7 @@ class TODOTest {
         val inst = PartiallyImplementedClass()
 
         assertNotImplemented { inst.prop }
-//        assertNotImplemented{ inst.method1() }
+        assertNotImplemented{ inst.method1() }
         assertNotImplemented { inst.method2() }
         assertNotImplemented { inst.method4() }
         assertNotImplementedWithMessage("what if false") { inst.method3(false, "test") }