Introduce OptionalExpectation for annotations missing on some platforms

This commits adds a new annotation OptionalExpectation to the standard
library, which is experimental. To enable its usage, either pass
'-Xuse-experimental=kotlin.ExperimentalMultiplatform' as a compiler
argument, or '-Xuse-experimental=kotlin.Experimental' and also annotate
each usage with `@UseExperimental(ExperimentalMultiplatform::class)`

 #KT-18882 Fixed

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -12078,6 +12078,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/jvmName/functionName.kt");
         }
 
+        @TestMetadata("loadJvmName.kt")
+        public void testLoadJvmName() throws Exception {
+            runTest("compiler/testData/codegen/box/jvmName/loadJvmName.kt");
+        }
+
         @TestMetadata("multifileClass.kt")
         public void testMultifileClass() throws Exception {
             runTest("compiler/testData/codegen/box/jvmName/multifileClass.kt");
@@ -13440,6 +13445,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/multiplatform/noArgActualConstructor.kt");
         }
 
+        @TestMetadata("optionalExpectation.kt")
+        public void testOptionalExpectation() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/optionalExpectation.kt");
+        }
+
         @TestMetadata("compiler/testData/codegen/box/multiplatform/defaultArguments")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)