asan_ubsan: mtr path fix

As this isn't an out of tree build, the mtr must be run
from the mysql-test directory otherwise:

sh -c 'MTR_FEEDBACK_PLUGIN=1 ASAN_OPTIONS="abort_on_error=1" LSAN_OPTIONS="print_suppressions=0,suppressions=$PWD/mysql-test/lsan.supp" mysql-test/mysql-test-run.pl --verbose-restart --force --retry=3 --max-save-core=2 --max-save-datadir=10 --max-test-fail=20 --mem --parallel=$(expr 20 \* 2)'
 in dir /home/buildbot/amd64-debian-12-asan-ubsan/build (timeout 950 secs)
 watching logfiles {'syslog': '/var/log/syslog'}
 argv: [b'sh', b'-c', b'MTR_FEEDBACK_PLUGIN=1 ASAN_OPTIONS="abort_on_error=1" LSAN_OPTIONS="print_suppressions=0,suppressions=$PWD/mysql-test/lsan.supp" mysql-test/mysql-test-run.pl --verbose-restart --force --retry=3 --max-save-core=2 --max-save-datadir=10 --max-test-fail=20 --mem --parallel=$(expr 20 \\* 2)']
 environment:
  BUILDMASTER=100.64.100.1
  BUILDMASTER_PORT=9992
  CARGO_NET_GIT_FETCH_WITH_CLI=true
  HOME=/home/buildbot
  HOSTNAME=2d2d22f108aa
  LC_CTYPE=C.UTF-8
  MTR_PRINT_CORE=detailed
  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
  PWD=/home/buildbot/amd64-debian-12-asan-ubsan/build
  WORKERNAME=hz-bbw2-docker-debian-12
  WSREP_PROVIDER=/usr/lib/galera/libgalera_smm.so
 using PTY: False
**** ERROR **** You must start mysql-test-run from the mysql-test/ directory
program finished with exit code 1

ref: https://buildbot.mariadb.org/#/builders/588/builds/7217

master-docker-nonstandard/master.cfg

@@ -493,7 +493,7 @@ f_asan_ubsan_build.addStep(
             "sh",
             "-c",
             util.Interpolate(
-                'MTR_FEEDBACK_PLUGIN=1 ASAN_OPTIONS="abort_on_error=1" LSAN_OPTIONS="print_suppressions=0,suppressions=$PWD/mysql-test/lsan.supp" mysql-test/mysql-test-run.pl --verbose-restart --force --retry=3 --max-save-core=2 --max-save-datadir=10 --max-test-fail=20 --mem --parallel=$(expr %(kw:jobs)s \* 2)',
+                'cd mysql-test && MTR_FEEDBACK_PLUGIN=1 ASAN_OPTIONS="abort_on_error=1" LSAN_OPTIONS="print_suppressions=0,suppressions=$PWD/lsan.supp" ./mysql-test-run.pl --verbose-restart --force --retry=3 --max-save-core=2 --max-save-datadir=10 --max-test-fail=20 --mem --parallel=$(expr %(kw:jobs)s \* 2)',
                 jobs=util.Property("jobs", default="$(getconf _NPROCESSORS_ONLN)"),
             ),
         ],