Support new scheme of compilation of OptionalExpectation annotations

Instead of generating these annotation classes as package-private on
JVM, serialize their metadata to the .kotlin_module file, and load it
when compiling dependent multiplatform modules.

The problem with generating them as package-private was that
kotlin-stdlib for JVM would end up declaring symbols from other
platforms, which would include some annotations from package
kotlin.native. But using that package is discouraged by some tools
because it has a Java keyword in its name. In particular, jlink refused
to work with such artifact altogether (KT-21266).

 #KT-38652 Fixed

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/JvmPackagePartProviderBase.kt

@@ -5,9 +5,11 @@
 
 package org.jetbrains.kotlin.load.kotlin
 
+import org.jetbrains.kotlin.descriptors.SourceElement
 import org.jetbrains.kotlin.metadata.jvm.deserialization.ModuleMapping
 import org.jetbrains.kotlin.metadata.jvm.deserialization.PackageParts
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.serialization.deserialization.ClassData
 import org.jetbrains.kotlin.serialization.deserialization.MetadataPartProvider
 
 abstract class JvmPackagePartProviderBase<MappingsKey> : PackagePartProvider, MetadataPartProvider {
@@ -51,4 +53,18 @@ abstract class JvmPackagePartProviderBase<MappingsKey> : PackagePartProvider, Me
             if (name == moduleName) mapping.moduleData.annotations.map(ClassId::fromString) else null
         }.flatten()
     }
+
+    override fun getAllOptionalAnnotationClasses(): List<ClassData> =
+        loadedModules.flatMap { module ->
+            getAllOptionalAnnotationClasses(module.mapping)
+        }
+
+    companion object {
+        fun getAllOptionalAnnotationClasses(module: ModuleMapping): List<ClassData> {
+            val data = module.moduleData
+            return data.optionalAnnotations.map { proto ->
+                ClassData(data.nameResolver, proto, module.version, SourceElement.NO_SOURCE)
+            }
+        }
+    }
 }

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/PackagePartProvider.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.load.kotlin
 
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.serialization.deserialization.ClassData
 
 interface PackagePartProvider {
     /**
@@ -19,9 +20,13 @@ interface PackagePartProvider {
 
     fun getAnnotationsOnBinaryModule(moduleName: String): List<ClassId>
 
+    fun getAllOptionalAnnotationClasses(): List<ClassData>
+
     object Empty : PackagePartProvider {
         override fun findPackageParts(packageFqName: String): List<String> = emptyList()
 
         override fun getAnnotationsOnBinaryModule(moduleName: String): List<ClassId> = emptyList()
+
+        override fun getAllOptionalAnnotationClasses(): List<ClassData> = emptyList()
     }
 }