[Commonizer] Lookup common descriptors that don't participate in commonization (for tests only)

This is necessary to run integration tests with fake declarations from
Kotlin/Native stdlib that are absent in stdlib-common.

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/Parameters.kt

@@ -23,6 +23,9 @@ class Parameters(
             field = value
         }
 
+    // only for test purposes
+    internal var commonModulesProvider: ModulesProvider? = null
+
     fun addTarget(targetProvider: TargetProvider): Parameters {
         require(targetProvider.target !in _targetProviders) { "Target ${targetProvider.target} is already added" }
         _targetProviders[targetProvider.target] = targetProvider

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/builder/context.kt

@@ -216,7 +216,10 @@ fun CirRootNode.createGlobalBuilderComponents(
         }
 
         val lazyModulesLookupTable = storageManager.createLazyValue {
-            val source = if (isCommon) emptyMap() else parameters.targetProviders[index].modulesProvider.loadModules()
+            val source = if (isCommon)
+                parameters.commonModulesProvider?.loadModules() ?: emptyMap()
+            else
+                parameters.targetProviders[index].modulesProvider.loadModules()
             THashMap(source)
         }
 

native/commonizer/tests/org/jetbrains/kotlin/descriptors/commonizer/AbstractCommonizationFromSourcesTest.kt

@@ -253,7 +253,11 @@ private class AnalyzedModules(
         check(originalPlatformModules.keys == commonizedPlatformModules.keys)
     }
 
-    fun toCommonizationParameters(): Parameters = originalPlatformModules.mapValues { it.value.module }.toCommonizationParameters()
+    fun toCommonizationParameters(): Parameters {
+        val parameters = originalPlatformModules.mapValues { it.value.module }.toCommonizationParameters()
+        parameters.commonModulesProvider = MockModulesProvider(commonizedCommonModule.module)
+        return parameters
+    }
 
     companion object {
         fun create(