z80: remove the de-optimisation pragmas from z80mem.cpp. (#755)

source/Z80VICE/z80mem.cpp

@@ -141,10 +141,6 @@ static void REGPARM2 store_unconnected_io(WORD addr, BYTE value)
 //    log_message(z80mem_log, "Store to unconnected IO %04x %02x", addr, value);	// [AppleWin-TC]
 }
 
-#ifdef _MSC_VER
-#pragma optimize("",off)
-#endif
-
 void z80mem_initialize(void)
 {
 	int i, j;
@@ -412,10 +408,6 @@ void z80mem_initialize(void)
 #endif
 }
 
-#ifdef _MSC_VER
-#pragma optimize("",on)
-#endif
-
 void z80mem_set_bank_pointer(BYTE **base, int *limit)
 {
     bank_base = base;