Avoid flaking in message_extraction tests by doing everything in a temp directory

pkg/intl/test/message_extraction/foo_messages_fr.dart

Index: pkg/intl/test/message_extraction/foo_messages_fr.dart
diff --git a/pkg/intl/test/message_extraction/foo_messages_fr.dart b/pkg/intl/test/message_extraction/foo_messages_fr.dart
deleted file mode 100644
index 7be3c2a9cb86c7df4d38f683c18c4b9e4123ea32..0000000000000000000000000000000000000000
--- a/pkg/intl/test/message_extraction/foo_messages_fr.dart
+++ /dev/null
@@ -1,101 +0,0 @@
-/**
- * DO NOT EDIT. This is code generated via pkg/intl/generate_localized.dart
- * This is a library that provides messages for a fr locale. All the
- * messages from the main program should be duplicated here with the same
- * function name.
- */
-
-library messages_fr;
-import 'package:intl/intl.dart';
-import 'package:intl/message_lookup_by_library.dart';
-
-final messages = new MessageLookup();
-
-class MessageLookup extends MessageLookupByLibrary {
-
-  get localeName => 'fr';
-  static alwaysTranslated() => "Cette chaîne est toujours traduit";
-
-  static differentNameSameContents() => "Bonjour tout le monde";
-
-  static escapable() => "Escapes: \n\r\f\b\t\v.";
-
-  static leadingQuotes() => "\"Soi-disant\"";
-
-  static message1() => "Il s\'agit d\'un message";
-
-  static message2(x) => "Un autre message avec un seul paramètre $x";
-
-  static message3(a, b, c) => "Caractères qui doivent être échapper, par exemple barres \\ dollars \${ (les accolades sont ok), et xml/html réservés <& et des citations \" avec quelques paramètres ainsi $a, $b, et $c";
-
-  static method() => "Cela vient d\'une méthode";
-
-  static multiLine() => "Cette message prend plusiers lignes.";
-
-  static nestedMessage(names, number, combinedGender, place) => "${Intl.gender(combinedGender, female: '${Intl.plural(number, one: '$names était allée à la $place', other: '$names étaient allées à la $place')}', other: '${Intl.plural(number, zero: 'Personne n\'avait allé à la $place', one: '${names} était allé à la $place', other: '${names} étaient allés à la $place')}')}";
-
-  static nestedOuter(number, gen) => "${Intl.plural(number, other: '${Intl.gender(gen, male: '$number homme', other: '$number autre')}')}";
-
-  static nestedSelect(currency, amount) => "${Intl.select(currency, {'CDN': '${Intl.plural(amount, one: '$amount dollar Canadien', other: '$amount dollars Canadiens')}', 'other': 'Nimporte quoi', })}";
-
-  static nonLambda() => "Cette méthode n\'est pas un lambda";
-
-  static notAlwaysTranslated() => "Ce manque certaines traductions";
-
-  static originalNotInBMP() => "Anciens caractères grecs jeux du pendu: 𐅆𐅇.";
-
-  static outerGender(g) => "${Intl.gender(g, female: 'femme', male: 'homme', other: 'autre')}";
-
-  static outerPlural(n) => "${Intl.plural(n, zero: 'rien', one: 'un', other: 'quelques-uns')}";
-
-  static outerSelect(currency, amount) => "${Intl.select(currency, {'CDN': '$amount dollars Canadiens', 'other': '$amount certaine devise ou autre.', })}";
-
-  static pluralThatFailsParsing(noOfThings) => "${Intl.plural(noOfThings, one: '1 chose:', other: '$noOfThings choses:')}";
-
-  static plurals(num) => "${Intl.plural(num, zero: 'Est-ce que nulle est pluriel?', one: 'C\'est singulier', other: 'C\'est pluriel ($num).')}";
-
-  static sameContentsDifferentName() => "Bonjour tout le monde";
-
-  static rentAsVerb() => "louer";
-
-  static rentToBePaid() => "loyer";
-
-  static staticMessage() => "Cela vient d\'une méthode statique";
-
-  static trickyInterpolation(s) => "L\'interpolation est délicate quand elle se termine une phrase comme ${s}.";
-
-  static types(a, b, c) => "$a, $b, $c";
-
-  static whereTheyWentMessage(name, gender, place) => "${Intl.gender(gender, female: '${name} est allée à sa ${place}', male: '${name} est allé à sa ${place}', other: '${name} est allé à sa ${place}')}";
-
-
-  final messages = const {
-    "alwaysTranslated" : alwaysTranslated,
-    "differentNameSameContents" : differentNameSameContents,
-    "escapable" : escapable,
-    "leadingQuotes" : leadingQuotes,
-    "message1" : message1,
-    "message2" : message2,
-    "message3" : message3,
-    "method" : method,
-    "multiLine" : multiLine,
-    "nestedMessage" : nestedMessage,
-    "nestedOuter" : nestedOuter,
-    "nestedSelect" : nestedSelect,
-    "nonLambda" : nonLambda,
-    "notAlwaysTranslated" : notAlwaysTranslated,
-    "originalNotInBMP" : originalNotInBMP,
-    "outerGender" : outerGender,
-    "outerPlural" : outerPlural,
-    "outerSelect" : outerSelect,
-    "pluralThatFailsParsing" : pluralThatFailsParsing,
-    "plurals" : plurals,
-    "sameContentsDifferentName" : sameContentsDifferentName,
-    "rentAsVerb" : rentAsVerb,
-    "rentToBePaid" : rentToBePaid,
-    "staticMessage" : staticMessage,
-    "trickyInterpolation" : trickyInterpolation,
-    "types" : types,
-    "whereTheyWentMessage" : whereTheyWentMessage
-  };
-}