Update localizable strings to "full screen" from "fullscreen"

Update localizable strings to "full screen" from "fullscreen"
https://bugs.webkit.org/show_bug.cgi?id=170675
rdar://problem/28207034

Reviewed by Antoine Quint.

Source/WebCore:

For localizable strings, it should consistently be "full screen" instead of "fullscreen".

* English.lproj/Localizable.strings:
* English.lproj/modern-media-controls-localized-strings.js:
* platform/LocalizedStrings.cpp:
(WebCore::contextMenuItemTagExitVideoFullscreen):
(WebCore::localizedMediaControlElementString):
* platform/cocoa/LocalizedStringsCocoa.mm:
(WebCore::exitFullScreenButtonAccessibilityTitle):

Source/WebInspectorUI:

* UserInterface/Models/ScriptTimelineRecord.js:
(WebInspector.ScriptTimelineRecord.EventType.displayName): For localizable strings, it should consistently be
"full screen" instead of "fullscreen".

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@215182 268f45cc-cd09-0410-ab3c-d52691b4dbfc