Remove more unused things from CryCommon and CrySystem. (#709)

Lots of unrelated removals, I basically tried to remove everything exposed via gEnv that isn't used anymore, and following the threads found a few other things to remove also.

Code/CryEngine/CrySystem/LevelSystem/SpawnableLevelSystem.cpp

@@ -247,8 +247,6 @@ namespace LegacyLevelSystem
 
             auto pPak = gEnv->pCryPak;
 
-            m_pSystem->SetThreadState(ESubsys_Physics, false);
-
             ICVar* pSpamDelay = gEnv->pConsole->GetCVar("log_SpamDelay");
             float spamDelay = 0.0f;
             if (pSpamDelay)
@@ -343,8 +341,6 @@ namespace LegacyLevelSystem
 
         gEnv->pSystem->GetISystemEventDispatcher()->OnSystemEvent(ESYSTEM_EVENT_LEVEL_PRECACHE_START, 0, 0);
 
-        m_pSystem->SetThreadState(ESubsys_Physics, true);
-
         return true;
     }