Fix broken test in IE7 - case sensitivity for tiddlyFields
Fix broken test in IE7 - case sensitivity for tiddlyFields

The test was previously looking for tiddlyfields but the
ToggleTiddlerPrivacyPlugin under test looks for tiddlyFields.

The TiddlyWiki code uses tiddlyFields but there are other
plugins in this code base which use tiddlfields. I am
reluctant to change this until test coverage is better
understood.

TiddlySpace/tiddlyspace,TiddlySpace/tiddlyspace,TiddlySpace/tiddlyspace