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

pkg/intl/test/message_extraction/foo_messages_de_DE.dart

Index: pkg/intl/test/message_extraction/foo_messages_de_DE.dart
diff --git a/pkg/intl/test/message_extraction/foo_messages_de_DE.dart b/pkg/intl/test/message_extraction/foo_messages_de_DE.dart
deleted file mode 100644
index f4c55edfd090ace3e956b7fe0ab83e1129586493..0000000000000000000000000000000000000000
--- a/pkg/intl/test/message_extraction/foo_messages_de_DE.dart
+++ /dev/null
@@ -1,98 +0,0 @@
-/**
- * DO NOT EDIT. This is code generated via pkg/intl/generate_localized.dart
- * This is a library that provides messages for a de_DE locale. All the
- * messages from the main program should be duplicated here with the same
- * function name.
- */
-
-library messages_de_DE;
-import 'package:intl/intl.dart';
-import 'package:intl/message_lookup_by_library.dart';
-
-final messages = new MessageLookup();
-
-class MessageLookup extends MessageLookupByLibrary {
-
-  get localeName => 'de_DE';
-  static alwaysTranslated() => "Diese Zeichenkette wird immer übersetzt";
-
-  static differentNameSameContents() => "Hallo Welt";
-
-  static escapable() => "Escapes: \n\r\f\b\t\v.";
-
-  static leadingQuotes() => "\"Sogenannt\"";
-
-  static message1() => "Dies ist eine Nachricht";
-
-  static message2(x) => "Eine weitere Meldung mit dem Parameter $x";
-
-  static message3(a, b, c) => "Zeichen, die Flucht benötigen, zB Schrägstriche \\ Dollar \${ (geschweiften Klammern sind ok) und xml reservierte Zeichen <& und Zitate \" Parameter $a, $b und $c";
-
-  static method() => "Dies ergibt sich aus einer Methode";
-
-  static multiLine() => "Dieser String erstreckt sich über mehrere Zeilen erstrecken.";
-
-  static nestedMessage(names, number, combinedGender, place) => "${Intl.gender(combinedGender, female: '${Intl.plural(number, one: '$names ging in dem $place', other: '$names gingen zum $place')}', other: '${Intl.plural(number, zero: 'Niemand ging zu $place', one: '${names} ging zum $place', other: '${names} gingen zum $place')}')}";
-
-  static nestedOuter(number, gen) => "${Intl.plural(number, other: '${Intl.gender(gen, male: '$number Mann', other: '$number andere')}')}";
-
-  static nestedSelect(currency, amount) => "${Intl.select(currency, {'CDN': '${Intl.plural(amount, one: '$amount Kanadischer dollar', other: '$amount Kanadischen dollar')}', 'other': 'whatever', })}";
-
-  static nonLambda() => "Diese Methode ist nicht eine Lambda";
-
-  static originalNotInBMP() => "Antike griechische Galgenmännchen Zeichen: 𐅆𐅇";
-
-  static outerGender(g) => "${Intl.gender(g, female: 'Frau', male: 'Mann', other: 'andere')}";
-
-  static outerPlural(n) => "${Intl.plural(n, zero: 'Null', one: 'ein', other: 'einige')}";
-
-  static outerSelect(currency, amount) => "${Intl.select(currency, {'CDN': '$amount Kanadischen dollar', 'other': '$amount einige Währung oder anderen.', })}";
-
-  static pluralThatFailsParsing(noOfThings) => "${Intl.plural(noOfThings, one: 'eins:', other: '$noOfThings Dinge:')}";
-
-  static plurals(num) => "${Intl.plural(num, zero: 'Ist Null Plural?', one: 'Dies ist einmalig', other: 'Dies ist Plural ($num).')}";
-
-  static sameContentsDifferentName() => "Hallo Welt";
-
-  static rentAsVerb() => "mieten";
-
-  static rentToBePaid() => "Miete";
-
-  static staticMessage() => "Dies ergibt sich aus einer statischen Methode";
-
-  static trickyInterpolation(s) => "Interpolation ist schwierig, wenn es einen Satz wie dieser endet ${s}.";
-
-  static types(a, b, c) => "$a, $b, $c";
-
-  static whereTheyWentMessage(name, gender, place) => "${Intl.gender(gender, female: '${name} ging zu ihrem ${place}', male: '${name} ging zu seinem ${place}', other: '${name} ging zu seinem ${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,
-    "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
-  };
-}