WL#2331: Remove "sql-bench" from the MySQL BK trees and distributions

The MySQL Benchmark suite included in the MySQL BK trees (subdirectory
"sql-bench" is no longer actively maintained. Instead, there is a separate
"mysql-bench" BK tree that includes the updated files.

As discussed with PeterZ, the old "sql-bench" subdirectory should be removed
from the MySQL BK trees (starting with MySQL 4.1) to avoid confusion. Instead of
including the sql-bench in each binary and source distribution, it should be
offered for download as a separate package.

To avoid any breakage by the removal, the following files need to be
updated/checked:

 - Makefile.am/configure.in (there is an option --without-bench)
 - scripts/make_binary_distribution.sh
 - scripts/make_win_src_distribution.sh
 - support-files/mysql.spec.sh

Additionally, "Do-compile-all" needs to be updated to not run the
sql-bench/crash-me until we have updated the build scripts to run the bechmarks
from a separate package instead.