Cleanup the usage of the SQLITE_DISABLE_INTRINSIC compile-time option.

Remove the SQLITE_RUNTIME_BYTEORDER compile-time option.  Use
-DSQLITE_BYTEORDER=0 instead.  Fix a bug in R-Tree that occurs when compiling
on a known little-endian machine without the use of intrinsic byteswapping
functions.

FossilOrigin-Name: 798fb9d70d2e5f95e64237b04d6692360133381a

src/mutex_w32.c

@@ -87,8 +87,7 @@ void sqlite3MemoryBarrier(void){
   SQLITE_MEMORY_BARRIER;
 #elif defined(__GNUC__)
   __sync_synchronize();
-#elif !defined(SQLITE_DISABLE_INTRINSIC) && \
-      defined(_MSC_VER) && _MSC_VER>=1300
+#elif MSCV_VERSION>=1300
   _ReadWriteBarrier();
 #elif defined(MemoryBarrier)
   MemoryBarrier();