Flaky test: Segmentation fault in tst_controls::Imagine::Popup

agent:2019/01/11 06:05:40 build.go:193: PASS : tst_controls::Imagine::Popup::test_locale()
agent:2019/01/11 06:05:40 build.go:193: make: *** [check] Segmentation fault: 11
agent:2019/01/11 06:05:40 build.go:237: Process finished with error: exit status 2
agent:2019/01/11 06:05:40 build.go:196: Error reading from stdout/err: exit status 2
agent:2019/01/11 06:05:40 build.go:435: Executing scheduled instruction 1 of 2 - Upload all core dumps if there are some
agent:2019/01/11 06:05:40 build.go:377: No core files have been found, that is good
agent:2019/01/11 06:05:40 build.go:437:
agent:2019/01/11 06:05:40 build.go:435: Executing scheduled instruction 2 of 2 - Upload test results
agent:2019/01/11 06:05:40 storageclient.go:400: Collecting test results, archiving and uploading them
agent:2019/01/11 06:05:40 result.go:155: Collecting 5 test results ...
agent:2019/01/11 06:05:40 build.go:437:
agent:2019/01/11 06:05:40 agent.go:226: Test failed
agent:2019/01/11 06:05:40 agent.go:96: ERROR building: error unmarshalling testlib xml output ('/Users/qt/work/testresults/tests/auto/controls/imagine024545840'): 'XML syntax error on line 1800: unexpected EOF'.
Most likely the test has crashed
2019-01-11 06:05:40,562 INFO: Agent FINISHED FAIL: testing /Users/qt/work/qt/qtquickcontrols2/tests/auto/controls/imagine: qt/qtquickcontrols2/88a74acbfd35ab166f1a08a457ff372a222c82cd/MacOSMacOS_10_13x86_64MacOSMacOS_10_13x86_64Clangqtci-macos-10.13-x86_64-2-253f3dDebugAndRelease_Release/a449a188ef74fdaa2498f2b5ba9ea49a719c547c/Test

Build log: https://testresults.qt.io/logs/qt/qtquickcontrols2/88a74acbfd35ab166f1a08a457ff372a222c82cd/MacOSMacOS_10_13x86_64MacOSMacOS_10_13x86_64Clangqtci-macos-10.13-x86_64-2-253f3dDebugAndRelease_Release/a449a188ef74fdaa2498f2b5ba9ea49a719c547c/test_1549005860/log.txt.gz

Details: https://testresults.qt.io/coin/integration/qt/qtquickcontrols2/tasks/1548997937

Tested changes (refs/builds/qtci/5.12.1/1547185292):
https://codereview.qt-project.org/#/q/8706da907af641be74d78cab3aba28ec359f3577,n,z Add changes file for Qt 5.12.1