[FIR] Handle expect declarations in JVM backend

1. Do not generate bytecode for expect declarations

2. Serialize @OptionalExpectation annotations into .kotlin_module file

^KT-62931: Fixed

compiler/ir/backend.jvm/entrypoint/src/org/jetbrains/kotlin/backend/jvm/JvmIrCodegenFactory.kt

@@ -22,6 +22,8 @@ import org.jetbrains.kotlin.backend.jvm.ir.getKtFile
 import org.jetbrains.kotlin.backend.jvm.serialization.DisabledIdSignatureDescriptor
 import org.jetbrains.kotlin.backend.jvm.serialization.JvmIdSignatureDescriptor
 import org.jetbrains.kotlin.codegen.CodegenFactory
+import org.jetbrains.kotlin.codegen.addCompiledPartsAndSort
+import org.jetbrains.kotlin.codegen.loadCompiledModule
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.config.JVMConfigurationKeys
@@ -43,6 +45,7 @@ import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.library.metadata.DeserializedKlibModuleOrigin
 import org.jetbrains.kotlin.library.metadata.KlibModuleOrigin
+import org.jetbrains.kotlin.metadata.jvm.JvmModuleProtoBuf
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi2ir.Psi2IrConfiguration
 import org.jetbrains.kotlin.psi2ir.Psi2IrTranslator
@@ -53,6 +56,7 @@ import org.jetbrains.kotlin.psi2ir.generators.fragments.EvaluatorFragmentInfo
 import org.jetbrains.kotlin.psi2ir.generators.fragments.FragmentContext
 import org.jetbrains.kotlin.psi2ir.preprocessing.SourceDeclarationsPreprocessor
 import org.jetbrains.kotlin.resolve.CleanableBindingContext
+import org.jetbrains.kotlin.serialization.StringTableImpl
 import org.jetbrains.kotlin.utils.IDEAPlatforms
 import org.jetbrains.kotlin.utils.IDEAPluginsCompatibilityAPI
 
@@ -370,6 +374,50 @@ open class JvmIrCodegenFactory(
         // TODO: split classes into groups connected by inline calls; call this after every group
         //       and clear `JvmBackendContext.classCodegens`
         state.afterIndependentPart()
+
+        generateModuleMetadata(input)
+    }
+
+    private fun generateModuleMetadata(result: CodegenFactory.CodegenInput) {
+        val backendContext = (result as JvmIrCodegenInput).context
+        val builder = JvmModuleProtoBuf.Module.newBuilder()
+        val stringTable = StringTableImpl()
+
+        backendContext.state.loadCompiledModule()?.moduleData?.run {
+            // In incremental compilation scenario, we might already have some serialized optionalAnnotations from the previous run
+            // In this case, we first initialize string table with the serialized one
+            // See jps/jps-plugin/testData/incremental/multiModule/multiplatform/custom/modifyOptionalAnnotationUsage for example
+            val nameResolver = nameResolver
+            repeat(nameResolver.strings.stringCount) { stringIndex ->
+                stringTable.addString(nameResolver.strings.getString(stringIndex))
+            }
+            repeat(nameResolver.qualifiedNames.qualifiedNameCount) { nameIndex ->
+                val qualifiedName = nameResolver.qualifiedNames.getQualifiedName(nameIndex)
+                stringTable.addQualifiedName(qualifiedName)
+            }
+            // Then add the annotations themselves, unless they are in dirty sources, i.e. contained in backendContext.optionalAnnotations
+            for (proto in optionalAnnotations) {
+                val name = nameResolver.getQualifiedClassName(proto.fqName)
+                if (backendContext.optionalAnnotations.none { metadata -> metadata.name?.asString() == name }) {
+                    builder.addOptionalAnnotationClass(proto)
+                }
+            }
+        }
+
+        for (part in backendContext.state.factory.packagePartRegistry.parts.values.addCompiledPartsAndSort(backendContext.state)) {
+            part.addTo(builder)
+        }
+
+        for (metadata in backendContext.optionalAnnotations) {
+            val serializer = backendContext.backendExtension.createModuleMetadataSerializer(backendContext)
+            builder.addOptionalAnnotationClass(serializer.serializeOptionalAnnotationClass(metadata, stringTable))
+        }
+
+        val (stringTableProto, qualifiedNameTableProto) = stringTable.buildProto()
+        builder.setStringTable(stringTableProto)
+        builder.setQualifiedNameTable(qualifiedNameTableProto)
+
+        backendContext.state.factory.setModuleMapping(builder.build())
     }
 
     fun generateModuleInFrontendIRMode(