Extend import resolution for library-to-source analysis

Use composite importing scope for references when resolution anchors are enabled.
Composite scope provides additional descriptors from scope of resolution anchor module.
Overriding old importing scope with a new one is not possible as it breaks library
dependencies on other libraries, which are inaccessible in anchor scope (scope for sources).

KT-24309 In Progress

compiler/config/src/org/jetbrains/kotlin/config/AnalysisFlags.kt

@@ -47,4 +47,7 @@ object AnalysisFlags {
 
     @JvmStatic
     val reportErrorsOnIrDependencies by AnalysisFlag.Delegates.Boolean
+
+    @JvmStatic
+    val libraryToSourceAnalysis by AnalysisFlag.Delegates.Boolean
 }

compiler/config/src/org/jetbrains/kotlin/config/CommonConfigurationKeys.kt

@@ -61,3 +61,6 @@ var CompilerConfiguration.languageVersionSettings: LanguageVersionSettings
 
 val LanguageVersionSettings.isTypeRefinementEnabled: Boolean
     get() = getFlag(AnalysisFlags.useTypeRefinement)
+
+val LanguageVersionSettings.isLibraryToSourceAnalysisEnabled: Boolean
+    get() = getFlag(AnalysisFlags.libraryToSourceAnalysis)