Revert "[K2/N] KT-57026, KT-57208: Adjust Native & JS test infrastructures for MPP testing"

This reverts commit 6964121c15.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/Fir2Ir.kt

@@ -71,9 +71,6 @@ internal fun PhaseContext.fir2Ir(
     ).also {
         (it.irModuleFragment.descriptor as? FirModuleDescriptor)?.let { it.allDependencyModules = librariesDescriptors }
     }
-    assert(fir2irResult.irModuleFragment.name.isSpecial) {
-        "`${fir2irResult.irModuleFragment.name}` must be Name.special, since it's required by KlibMetadataModuleDescriptorFactoryImpl.createDescriptorOptionalBuiltIns()"
-    }
 
     val symbols = createKonanSymbols(fir2irResult)
     // TODO KT-55580 Invoke CopyDefaultValuesToActualPhase, same as PsiToir phase does.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/FirFrontend.kt

@@ -42,7 +42,7 @@ internal fun PhaseContext.firFrontend(input: KotlinCoreEnvironment): FirOutput {
     val resolvedLibraries: List<KotlinResolvedLibrary> = config.resolvedLibraries.getFullResolvedList()
 
     val sessionsWithSources = prepareNativeSessions(
-            ktFiles, configuration, mainModuleName, resolvedLibraries, dependencyList,
+            ktFiles, configuration, mainModuleName.asString(), resolvedLibraries, dependencyList,
             extensionRegistrars, isCommonSourceForPsi, fileBelongsToModuleForPsi
     )