FIR: Optimize iteration

compiler/fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -430,11 +430,14 @@ class RawFirBuilder(val session: FirSession) {
                             for (typeArgument in qualifier!!.typeArguments) {
                                 firQualifier.typeArguments += typeArgument.convert<FirTypeProjection>()
                             }
-                            userType.qualifier.add(0, firQualifier)
+                            userType.qualifier.add(firQualifier)
 
                             qualifier = qualifier.qualifier
                             referenceExpression = qualifier?.referenceExpression
                         } while (referenceExpression != null)
+
+                        userType.qualifier.reverse()
+
                         userType
                     } else {
                         FirErrorTypeImpl(session, typeReference, "Incomplete user type")

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/impl/FirUserTypeImpl.kt

@@ -13,14 +13,13 @@ import org.jetbrains.kotlin.fir.types.FirQualifierPart
 import org.jetbrains.kotlin.fir.types.FirTypeProjection
 import org.jetbrains.kotlin.fir.types.FirUserType
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
-import java.util.*
 
 class FirUserTypeImpl(
     session: FirSession,
     psi: PsiElement?,
     isNullable: Boolean
 ) : FirAbstractAnnotatedType(session, psi, isNullable), FirUserType {
-    override val qualifier = LinkedList<FirQualifierPart>()
+    override val qualifier = mutableListOf<FirQualifierPart>()
 
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement {
         for (part in qualifier) {