mtr to xml-report of memory leaks

From MDEV-38391 the MTR will not output a XML result for a memory leak:

$ mysql-test/mtr --skip-stack-trace innodb.import_hidden_fts_debug --xml-report=/tmp/r.xml
Logging: /home/dan/repos/mariadb-server-10.11/mysql-test/mariadb-test-run.pl --skip-stack-trace innodb.import_hidden_fts_debug --xml-report=/tmp/r.xml
VS config:
vardir: /home/dan/repos/build-mariadb-server-10.11-debug/mysql-test/var
Checking leftover processes...
Removing old var directory...
Creating var directory '/home/dan/repos/build-mariadb-server-10.11-debug/mysql-test/var'...
Checking supported features...
MariaDB Version 10.11.15-MariaDB-asan-debug

• SSL connections supported
• binaries are debug compiled
  ls -la /tmp/. - binaries built with wsrep patch
  Collecting tests...
  Installing system database...

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

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

worker[01] Using MTR_BUILD_THREAD 300, with reserved ports 19000..19029
innodb.import_hidden_fts_debug [ pass ] 1284
***Warnings generated in error logs during shutdown after running tests: innodb.import_hidden_fts_debug

==8508==ERROR: LeakSanitizer: detected memory leaks
SUMMARY: AddressSanitizer: 2096 byte(s) leaked in 2 allocation(s).
251222 10:45:39 [ERROR] /home/dan/repos/build-mariadb-server-10.11-debug/sql/mariadbd got signal 6 ;

--------------------------------------------------------------------------
The servers were restarted 0 times
Spent 1.284 of 16 seconds executing testcases

Warnings in log: All 1 tests were successful.

Errors/warnings were found in logfiles during server shutdown after running the
following sequence(s) of tests:
innodb.import_hidden_fts_debug
mysql-test-run: *** ERROR: There where errors/warnings in server logs after running test cases.

$ ls /tmp/r.xml
/tmp/r.xml

$ more /tmp/r.xml
<?xml version="1.0" encoding="UTF-8"?>
<testsuites disabled="0" errors="" failures="0" name="" tests="1" time="1.284
">
<testsuite disabled="" errors="" failures="" hostname="bark" id="0" n
ame="innodb" package="" skipped="" tests="1" time="1.284" timestamp="2025-12-
21T23:45:39Z">
<testcase assertions="" classname="innodb" name="import_hidde
n_fts_debug" status="MTR_RES_PASSED" time="1.284" combinations="" />
</testsuite>
</testsuites>