[klib] Don't pass around metadata serialization closure

Pass the metadata serializer instance instead. This allows to further
reduce code duplication by introducing the common interface
`KlibSingleFileMetadataSerializer` for abstracting away K1 and K2
representation of a source file, as well as reusing
`Fir2KlibMetadataSerializer` across different backends.

KT-64392

compiler/tests/org/jetbrains/kotlin/klib/FilePathsInKlibTest.kt

@@ -74,9 +74,6 @@ class FilePathsInKlibTest : CodegenTestCase() {
             module.getModuleDescriptor(it)
         }
 
-        val metadataSerializer =
-            KlibMetadataIncrementalSerializer(module.compilerConfiguration, module.project, module.jsFrontEndResult.hasErrors)
-
         val diagnosticReporter = DiagnosticReporterFactory.createPendingReporter()
         generateKLib(
             module,
@@ -85,10 +82,8 @@ class FilePathsInKlibTest : CodegenTestCase() {
             jsOutputName = MODULE_NAME,
             icData = icData,
             moduleFragment = moduleFragment,
-            diagnosticReporter = diagnosticReporter
-        ) { file ->
-            metadataSerializer.serializeScope(file, module.jsFrontEndResult.bindingContext, moduleFragment.descriptor)
-        }
+            diagnosticReporter = diagnosticReporter,
+        )
     }
 
     private fun setupEnvironment(): CompilerConfiguration {