Revert of Fix build for iOS after "Make nanobench and dm be usable from Chromium build" (patchset #1 id:1 of https://codereview.chromium.org/716413003/)

Reason for revert:
Causes breakages on Mac.

Original issue's description:
> Fix build for iOS after "Make nanobench and dm be usable from Chromium build"
>
> Fix build for iOS after "Make nanobench and dm be usable from Chromium
> build"
>
> BUG=skia:2992
>
> Committed: https://skia.googlesource.com/skia/+/0935aed2787eb79629125bdfef9aba2a6a283ef7

TBR=robertphillips@google.com,kkinnunen@nvidia.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2992

Review URL: https://codereview.chromium.org/724813002
diff --git a/gyp/iOSShell.gyp b/gyp/iOSShell.gyp
index 2a9698a..ac2ed30 100644
--- a/gyp/iOSShell.gyp
+++ b/gyp/iOSShell.gyp
@@ -67,7 +67,6 @@
             '../experimental/iOSSampleApp/Shared',
             '../include/utils/ios',
             '../src/views/mac',
-            '../bench',
           ],
           'xcode_settings' : {
             'INFOPLIST_FILE' : '../experimental/iOSShell/iOSShell-Info.plist',