Move the vfstrace extension out of src/ over into ext/misc/ where it belongs.

Make it part of the standard build for the CLI.  Bring some of the vfstrace
output up-to-date.

FossilOrigin-Name: 055b97de8d2397987d72dbab1cde78ece2d1c066e95042b4ed6b7b36b2cf9006

tool/build-shell.sh

@@ -17,5 +17,5 @@ gcc -o sqlite3 -g -Os -I. \
    -DSQLITE_ENABLE_RTREE \
    -DHAVE_READLINE \
    ../sqlite/src/shell.c \
-   ../sqlite/src/test_vfstrace.c \
+   ../sqlite/ext/misc/vfstrace.c \
    sqlite3.c -ldl -lreadline -lncurses

tool/pagesig.c

@@ -26,7 +26,7 @@
 ** the entire block.
 **
 ** For blocks of more than 16 bytes, the signature is a hex dump of the
-** first 8 bytes followed by a 64-bit has of the entire block.
+** first 8 bytes followed by a 64-bit hash of the entire block.
 */
 static void vlogSignature(unsigned char *p, int n, char *zCksum){
   unsigned int s0 = 0, s1 = 0;