[FIR JS] Implement FirJsExportDeclarationChecker

core/compiler.common.js/src/org/jetbrains/kotlin/name/JsStandardClassIds.kt

@@ -42,7 +42,7 @@ object JsStandardClassIds {
         val JsExport = "JsExport".jsId()
 
         @JvmField
-        val JsExportIgnore = ClassId(JsExport.asSingleFqName(), Name.identifier("Ignore"))
+        val JsExportIgnore = JsExport.createNestedClassId(Name.identifier("Ignore"))
 
         @JvmField
         val annotationsRequiringExternal = setOf(JsModule, JsQualifier)

core/compiler.common/src/org/jetbrains/kotlin/types/TypeSystemCommonBackendContext.kt

@@ -40,7 +40,6 @@ interface TypeSystemCommonBackendContext : TypeSystemContext {
 
     fun KotlinTypeMarker.makeNullable(): KotlinTypeMarker =
         asSimpleType()?.withNullability(true) ?: this
-
     fun TypeConstructorMarker.getPrimitiveType(): PrimitiveType?
     fun TypeConstructorMarker.getPrimitiveArrayType(): PrimitiveType?