SL-15177 Fix the way of counting for gTextureTimer

indra/newview/app_settings/settings.xml

indra/newview/llappviewer.cpp

indra/newview/llfloatertexturefetchdebugger.cpp

indra/newview/llfloatertexturefetchdebugger.h

indra/newview/llviewerstats.cpp

indra/newview/llviewerstats.h

indra/newview/llviewertexture.h

indra/newview/llviewertexturelist.cpp

indra/newview/llviewertexturelist.h

...newview/skins/default/xui/en/floater_scene_load_stats.xml

...w/skins/default/xui/en/floater_texture_fetch_debugger.xml