[AA] Add KotlinPackageProviderMerger

- In parallel to Kotlin declaration provider merging, we need a proper
  merging strategy for package providers as well, because resolve
  extensions may define additional package providers.
- Additionally, other non-scope-based package providers may be added in
  the future, and the merger preserves these out of the box.

^KT-61791

analysis/analysis-api-impl-base/tests/org/jetbrains/kotlin/analysis/api/impl/base/test/configurators/AnalysisApiBaseTestServiceRegistrar.kt

@@ -99,6 +99,7 @@ object AnalysisApiBaseTestServiceRegistrar: AnalysisApiTestServiceRegistrar()  {
                 KotlinPackageProviderFactory::class.java,
                 KotlinStaticPackageProviderFactory(project, allSourceKtFiles + ktFilesForBinaries)
             )
+            registerService(KotlinPackageProviderMerger::class.java, KotlinStaticPackageProviderMerger(project))
             registerService(KotlinResolutionScopeProvider::class.java, KotlinByModulesResolutionScopeProvider::class.java)
         }
     }