[FIR] Type "top-level classifier names in package" as Name

- This is more consistent with "top-level callable names in package" and
  simplifies the set construction quite a bit, as we can avoid a lot of
  `asString` conversions.

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt

@@ -94,8 +94,11 @@ abstract class AbstractFirDeserializedSymbolProvider(
     }
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirCachedSymbolNamesProvider(session) {
-        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>? {
-            val classesInPackage = knownTopLevelClassesInPackage(packageFqName) ?: return null
+        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>? {
+            val classesInPackage = knownTopLevelClassesInPackage(packageFqName)
+                ?.mapTo(mutableSetOf()) { Name.identifier(it) }
+                ?.ifEmpty { emptySet() }
+                ?: return null
 
             if (packageFqName.asString() !in packageNamesForNonClassDeclarations) return classesInPackage
 
@@ -104,7 +107,7 @@ abstract class AbstractFirDeserializedSymbolProvider(
 
             return buildSet {
                 addAll(classesInPackage)
-                typeAliasNames.mapTo(this) { it.asString() }
+                addAll(typeAliasNames)
             }
         }
 

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt

@@ -88,9 +88,9 @@ open class FirBuiltinSymbolProvider(
         override fun getPackageNamesWithTopLevelCallables(): Set<String> =
             allPackageFragments.keys.mapTo(mutableSetOf()) { it.asString() }
 
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             allPackageFragments[packageFqName]?.flatMapTo(mutableSetOf()) { fragment ->
-                fragment.classDataFinder.allClassIds.map { it.shortClassName.asString() }
+                fragment.classDataFinder.allClassIds.map { it.shortClassName }
             }.orEmpty()
 
         override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> =