[FIR] Rewrite algorithm of generating declarations by plugins

Before there was separate global stage which asks extensions
  to generate new declarations. Now it is changed to provider
  like requests, so extensions will decide do they have declarations
  with specific classId/callableId or not

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/FirSessionFactory.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.fir.checkers.registerJvmCheckers
 import org.jetbrains.kotlin.fir.deserialization.ModuleDataProvider
 import org.jetbrains.kotlin.fir.deserialization.SingleModuleDataProvider
 import org.jetbrains.kotlin.fir.extensions.BunchOfRegisteredExtensions
+import org.jetbrains.kotlin.fir.extensions.FirExtensionDeclarationsSymbolProvider
 import org.jetbrains.kotlin.fir.extensions.extensionService
 import org.jetbrains.kotlin.fir.extensions.registerExtensions
 import org.jetbrains.kotlin.fir.java.FirCliSession
@@ -157,6 +158,12 @@ object FirSessionFactory {
                 )
             }
 
+            FirSessionConfigurator(this).apply {
+                registerCommonCheckers()
+                registerJvmCheckers()
+                init()
+            }.configure()
+
             val dependenciesSymbolProvider = FirDependenciesSymbolProviderImpl(this)
             register(
                 FirSymbolProvider::class,
@@ -165,6 +172,7 @@ object FirSessionFactory {
                     listOfNotNull(
                         firProvider.symbolProvider,
                         symbolProviderForBinariesFromIncrementalCompilation,
+                        FirExtensionDeclarationsSymbolProvider.create(this),
                         JavaSymbolProvider(this, projectEnvironment.getFirJavaFacade(this, moduleData, scope)),
                         dependenciesSymbolProvider,
                     )
@@ -177,11 +185,6 @@ object FirSessionFactory {
             )
 
             FirJvmDefaultErrorMessages.installJvmErrorMessages()
-            FirSessionConfigurator(this).apply {
-                registerCommonCheckers()
-                registerJvmCheckers()
-                init()
-            }.configure()
             projectEnvironment.registerAsJavaElementFinder(this)
         }
     }