Fixes audio crash and issues w/ audio playback (#1633)

This was caused by the main thread audio update not being called all the
time, especially Editor Game mode.

The crash was due to main thread containers not being processed and
emptied of their requests.

Signed-off-by: amzn-phist <52085794+amzn-phist@users.noreply.github.com>

Code/CryEngine/CrySystem/System.h

@@ -225,8 +225,6 @@ struct SSystemCVars
 
     int sys_FilesystemCaseSensitivity;
 
-    int sys_deferAudioUpdateOptim;
-
     AZ::IO::ArchiveVars archiveVars;
 
 #if defined(WIN32)
@@ -305,8 +303,6 @@ public:
     virtual bool UpdatePreTickBus(int updateFlags = 0, int nPauseMode = 0);
     virtual bool UpdatePostTickBus(int updateFlags = 0, int nPauseMode = 0);
     virtual bool UpdateLoadtime();
-    virtual void DoWorkDuringOcclusionChecks();
-    virtual bool NeedDoWorkDuringOcclusionChecks() { return m_bNeedDoWorkDuringOcclusionChecks; }
 
     ////////////////////////////////////////////////////////////////////////
     // CrySystemRequestBus interface implementation
@@ -737,7 +733,6 @@ protected: // -------------------------------------------------------------
     typedef std::list<SErrorMessage> TErrorMessages;
     TErrorMessages m_ErrorMessages;
     bool m_bHasRenderedErrorMessage;
-    bool m_bNeedDoWorkDuringOcclusionChecks;
 
     ESystemEvent m_eRuntimeState;
     bool m_bIsAsserting;