Revert "Add NSAllowsArbitraryLoadsInWebContent Info plist key"

This reverts commit 12ac640.

Reason for revert: introduces crbug.com/745945

Original change's description:
> Add NSAllowsArbitraryLoadsInWebContent Info plist key
>
> The old NSAllowsArbitraryLoads key is still required for backwards
> compatibility when running on old iOS versions.
>
> EarlGrey test targets need to download insecure images from
> browsingtest.appspot.com so add it as an exception domain in
> EarlGreyAddition+Info.plist.
>
> Bug: 622747
> Change-Id: Ide26330939035cd8a876612dc659c48a6e2bd9fc
> Reviewed-on: https://chromium-review.googlesource.com/568791
> Reviewed-by: Eugene But <eugenebut@chromium.org>
> Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#486376}

TBR=eugenebut@chromium.org, michaeldo@chromium.org


(cherry picked from commit f0b26ec)

Bug: 622747
Change-Id: If3b5cb105118d301fba67ef9b1d4c46859399022
Reviewed-on: https://chromium-review.googlesource.com/580524
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#488561}
Reviewed-on: https://chromium-review.googlesource.com/586968
Cr-Commit-Position: refs/branch-heads/3163@{#58}
Cr-Branched-From: ff259ba-refs/heads/master@{#488528}

Author: Eugene But

ios/chrome/app/resources/EarlGreyAddition+Info.plist

@@ -6,18 +6,5 @@
 	<string>${EG_MAIN_APPLICATION_DELEGATE}</string>
 	<key>UIFileSharingEnabled</key>
 	<true/>
-	<key>NSAppTransportSecurity</key>
-	<dict>
-		<key>NSExceptionDomains</key>
-		<dict>
-			<key>browsingtest.appspot.com</key>
-			<dict>
-				<key>NSExceptionAllowsInsecureHTTPLoads</key>
-				<true/>
-				<key>NSIncludesSubdomains</key>
-				<true/>
-			</dict>
-		</dict>
-	</dict>
 </dict>
 </plist>

ios/chrome/app/resources/Info.plist

@@ -75,8 +75,6 @@
 	<dict>
 		<key>NSAllowsArbitraryLoads</key>
 		<true/>
-		<key>NSAllowsArbitraryLoadsInWebContent</key>
-		<true/>
 	</dict>
 	<key>NSUserActivityTypes</key>
 	<array>