Attempt to fix failing tests on the windows bots

Change-Id: I84d16ad2708d4d18b06cdd454d1276b0d3ef8bc0
Reviewed-on: https://dart-review.googlesource.com/69001
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart

@@ -1494,7 +1494,7 @@ class B extends A {
     // SimpleIdentifier  HideCombinator  ImportDirective
     addSource('/testAB.dart', '''
         library libAB;
-        part '/partAB.dart';
+        part 'partAB.dart';
         class A { }
         class B { }''');
     addSource('/partAB.dart', '''
@@ -1518,7 +1518,7 @@ class B extends A {
     // SimpleIdentifier  HideCombinator  ImportDirective
     addSource('/testAB.dart', '''
         library libAB;
-        part '/partAB.dart';
+        part 'partAB.dart';
         class A { }
         class B { }''');
     addSource('/partAB.dart', '''
@@ -3615,7 +3615,7 @@ class B extends A {
     addTestSource('''
         library libA;
         import "${convertPathForImport('/testB.dart')}";
-        part "/testA.dart";
+        part "testA.dart";
         class A { A({String boo: 'hoo'}) { } }
         main() {new ^}
         var m;''');

pkg/analysis_server/test/services/completion/dart/library_prefix_contributor_test.dart

@@ -62,10 +62,10 @@ class H { }
 int T3;
 var _T4;'''); // not imported
     addTestSource('''
-import "/testAB.dart";
-import "/testCD.dart" hide D;
-import "/testEEF.dart" show EE;
-import "/testG.dart" as g;
+import "testAB.dart";
+import "testCD.dart" hide D;
+import "testEEF.dart" show EE;
+import "testG.dart" as g;
 int T5;
 var _T6;
 String get T7 => 'hello';
@@ -109,10 +109,10 @@ class H { }
 int T3;
 var _T4;'''); // not imported
     addTestSource('''
-import "/testAB.dart";
-import "/testCD.dart" hide D;
-import "/testEEF.dart" show EE;
-import "/testG.dart" as g;
+import "testAB.dart";
+import "testCD.dart" hide D;
+import "testEEF.dart" show EE;
+import "testG.dart" as g;
 int T5;
 var _T6;
 String get T7 => 'hello';
@@ -156,10 +156,10 @@ class H { }
 int T3;
 var _T4;'''); // not imported
     addTestSource('''
-import "/testAB.dart";
-import "/testCD.dart" hide D;
-import "/testEEF.dart" show EE;
-import "/testG.dart" as g;
+import "testAB.dart";
+import "testCD.dart" hide D;
+import "testEEF.dart" show EE;
+import "testG.dart" as g;
 int T5;
 var _T6;
 String get T7 => 'hello';
@@ -278,7 +278,7 @@ class A {foo(){var f; {var x;}}}
 class B {B(this.x, [String boo]) { } int x;}
 class C {C.bar({boo: 'hoo', int z: 0}) { } }''');
     addTestSource('''
-import "/testA.dart" as t;
+import "testA.dart" as t;
 import "dart:math" as math;
 main() {new ^ String x = "hello";}''');
     await computeSuggestions();
@@ -317,7 +317,7 @@ class B {B(this.x, [String boo]) { } int x;}
 class C {C.bar({boo: 'hoo', int z: 0}) { } }''');
     addSource('/testB.dart', '''
 library testB;
-import "/testA.dart" as t;
+import "testA.dart" as t;
 import "dart:math" as math;
 //part "$testFile"
 main() {new ^ String x = "hello";}''');