Disable Quarantine tests on platforms its not supported.

content/common/quarantine/quarantine_win.cc

Index: content/common/quarantine/quarantine_win.cc
diff --git a/content/common/quarantine/quarantine_win.cc b/content/common/quarantine/quarantine_win.cc
index 91eecc75e02d415468a2c53a52e3610f94d28c2a..53a3d9fab6d33dca1f3be61fa4faf4c6f624de48 100644
--- a/content/common/quarantine/quarantine_win.cc
+++ b/content/common/quarantine/quarantine_win.cc
@@ -348,4 +348,9 @@ bool IsFileQuarantined(const base::FilePath& file,
   return ZoneIdentifierPresentForFile(file);
 }
 
+// Only to be used in tests.
+bool IsQuarantineSupportedForTesting() {
+  return true;
+}
+
 }  // namespace content