tst_bench_qguimetatype fails in qt6 branches

Stdout:
cset: --> last message, executed args into cpuset "/user", new pid is: 1465602
********* Start testing of tst_QGuiMetaType *********
Config: Using QtTest library 6.2.0, Qt 6.2.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 9.3.0), ubuntu 20.04
PASS   : tst_QGuiMetaType::initTestCase()
QWARN  : tst_QGuiMetaType::constructInPlace() Trying to construct an instance of an invalid type, type id: 4111
QFATAL : tst_QGuiMetaType::constructInPlace() ASSERT failure in QTest::newRow(): "Data tag cannot be null", file src/testlib/qtestcase.cpp, line 2371
FAIL!  : tst_QGuiMetaType::constructInPlace() Received a fatal error.
   Loc: [Unknown file(0)]
Totals: 1 passed, 1 failed, 0 skipped, 0 blacklisted, 1ms
********* Finished testing of tst_QGuiMetaType *********
Stderr:
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-qt'