Disable test_import_short_absolute on Windows.

pkg/analyzer/test/src/summary/resynthesize_common.dart

Index: pkg/analyzer/test/src/summary/resynthesize_common.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_common.dart b/pkg/analyzer/test/src/summary/resynthesize_common.dart
index be1ba73935d0d1d346dc3dcf20e2d6aebb7b000d..bd880def890440bd0350be59c80f896b2d4894fb 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_common.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_common.dart
@@ -3434,6 +3434,12 @@ class D extends p.C {} // Prevent "unused import" warning
   }
 
   test_import_short_absolute() {
+    if (resourceProvider.pathContext.separator == '\\') {
+      // This test fails on Windows due to
+      // https://github.com/dart-lang/path/issues/18
+      // TODO(paulberry): reenable once that bug is addressed.
+      return;
+    }
     testFile = '/my/project/bin/test.dart';
     addLibrarySource('/a.dart', 'class C {}');
     checkLibrary('import "/a.dart"; C c;');