Cygwin is not needed for MSVC

Bug: v8:4742
Change-Id: I6f9583cd25c4a8b038e665ea18a20abf29d8b376
Reviewed-on: https://chromium-review.googlesource.com/471107Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Loo Rong Jie <loorongjie@gmail.com>
Cr-Commit-Position: refs/heads/master@{#44557}

DEPS

@@ -50,10 +50,6 @@ deps_os = {
     "v8/third_party/catapult":
       Var('chromium_url') + "/external/github.com/catapult-project/catapult.git" + "@" + "9a55abab029cb9ae94f5160ded11b09a4638a955",
   },
-  "win": {
-    "v8/third_party/cygwin":
-      Var("chromium_url") + "/chromium/deps/cygwin.git" + "@" + "c89e446b273697fadf3a10ff1007a97c0b7de6df",
-  }
 }
 
 recursedeps = [

gypfiles/standalone.gypi

@@ -866,6 +866,7 @@
             ],
           }],
         ],
+        'msvs_cygwin_shell': 0,
         'msvs_cygwin_dirs': ['<(DEPTH)/third_party/cygwin'],
         'msvs_disabled_warnings': [
           # C4091: 'typedef ': ignored on left of 'X' when no variable is