MDEV-15503: mtr fix --stracebb-5.5-anel

$glob_mysql_test_dir was the wrong directory for strace output as
it was for in-tree builds only so failed for:
* out of tree builds
* --parallel; and
* --mem

strace output wasn't saved.

strace-option never replaced existing arguments (so ammended
documentation).

strace-client didn't accept an argument as described.

Replaced specification of client with this with 'stracer' to be
consistent with --debugger option.

For consistency with debugger options, --client-strace was added to
execute the strace on the mysqltest.

Example:

$ mysql-test/mtr --strace --client-strace  --mem --parallel=3  main.select
Logging: /home/dan/software_projects/mariadb-server/mysql-test/mysql-test-run.pl  --strace --client-strace --mem --parallel=3 main.select
vardir: /home/dan/software_projects/build-mariadb-10.3/mysql-test/var
Checking leftover processes...
Removing old var directory...
Creating var directory '/home/dan/software_projects/build-mariadb-10.3/mysql-test/var'...
 - symlinking 'var' to '/dev/shm/var_auto_0v2E'
Checking supported features...
MariaDB Version 10.3.7-MariaDB
 - SSL connections supported
Collecting tests...
Installing system database...

==============================================================================

TEST                                  WORKER RESULT   TIME (ms) or COMMENT
--------------------------------------------------------------------------

worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019
worker[3]  - 'localhost:16040' was not free
worker[2] Using MTR_BUILD_THREAD 301, with reserved ports 16020..16039
worker[3] Using MTR_BUILD_THREAD 303, with reserved ports 16060..16079
main.select                              w1 [ pass ]   7310
--------------------------------------------------------------------------
The servers were restarted 0 times
Spent 7.310 of 11 seconds executing testcases

Completed: All 1 tests were successful.

$ find mysql-test/var/ -name \*strace -ls
  5213766   1212 -rw-r--r--   1  dan      dan       1237817 May 20 16:47 mysql-test/var/1/mysqltest.strace
  5214733  13016 -rw-r--r--   1  dan      dan      13328335 May 20 16:47 mysql-test/var/1/mysqld.1.strace

$ mysql-test/mtr --strace --client-strace --strace-option='-e' --strace-option='trace=openat'  --mem --parallel=3  main.select
...
$ find mysql-test/var/ -name \*strace -ls
  5220790      8 -rw-r--r--   1  dan      dan          6291 May 20 17:02 mysql-test/var/3/mysqltest.strace
  5224140    308 -rw-r--r--   1  dan      dan        314356 May 20 17:02 mysql-test/var/3/mysqld.1.strace
$ more mysql-test/var/3/mysqltest.strace
1692  openat(AT_FDCWD, "/home/dan/software_projects/mariadb-server/libmysql/.libs/tls/x86_64/x86_64/libpthread.so.0", O_RDONLY|O_CLOEXEC) =
-1 ENOENT (No such file or directory)
1692  openat(AT_FDCWD, "/home/dan/software_projects/mariadb-server/libmysql/.libs/tls/x86_64/libpthread.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOE
NT (No such file or directory)
....

0 files changed, 0 insertions, 0 deletions