[FIR] Allow all extensions register declaration predicates

compiler/fir/tree/src/org/jetbrains/kotlin/fir/extensions/FirExtension.kt

@@ -31,10 +31,8 @@ abstract class FirExtension(val session: FirSession) {
     fun interface Factory<out P : FirExtension> {
         fun create(session: FirSession): P
     }
-}
 
-abstract class FirPredicateBasedExtension(session: FirSession) : FirExtension(session) {
-    abstract fun FirDeclarationPredicateRegistrar.registerPredicates()
+    open fun FirDeclarationPredicateRegistrar.registerPredicates() {}
 }
 
 data class FirExtensionPointName(val name: Name) {

compiler/fir/tree/src/org/jetbrains/kotlin/fir/extensions/FirExtensionService.kt

@@ -36,14 +36,10 @@ class FirExtensionService(val session: FirSession) : ComponentArrayOwner<FirExte
     var registeredExtensionsSize: Int = 0
         private set
 
-    var registeredPredicateBasedExtensionsSize: Int = 0
-        private set
-
     @PluginServicesInitialization
     fun registerExtensions(extensionClass: KClass<out FirExtension>, extensionFactories: List<FirExtension.Factory<*>>) {
         registeredExtensionsSize += extensionFactories.size
         val extensions = extensionFactories.map { it.create(session) }
-        registeredPredicateBasedExtensionsSize += extensions.count { it is FirPredicateBasedExtension }
         registerComponent(
             extensionClass,
             extensions
@@ -60,6 +56,3 @@ val FirSession.extensionService: FirExtensionService by FirSession.sessionCompon
 
 val FirExtensionService.hasExtensions: Boolean
     get() = registeredExtensionsSize > 0
-
-val FirExtensionService.hasPredicateBasedExtensions: Boolean
-    get() = registeredPredicateBasedExtensionsSize > 0