Intermittent Unit Test Failure: VclComplexTextTest::testArabic

Over the years, I've probably done several hundred windows builds. Until now I have never been 
bitten an intermittent Unit Test failures. This month, I have started to see fairly regular failure 
of VclComplexTextTest::testArabic 3 out of ~15 builds.

Here are 2 separate examples of the Jenkins_Windows Tinderbox seeing the same failure in the past 2 
days:

https://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1537871271.4910

https://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1537949563.7757

Has anyone investigated this? Is there any way to search Jenkins logs to see when this failure 
first occurred? 

-Luke


[build CUT] drawinglayer_border
`anonymous namespace'::CanvasBitmapTest::runTest finished in: 841ms
C:/core/vcl/qa/cppunit/complextext.cxx:98:VclComplexTextTest::testArabic
equality assertion failed
- Expected: 72
- Actual  : 75

VclComplexTextTest::testArabic finished in: 971ms
VclComplexTextTest::testTdf95650 finished in: 527ms
C:/core/vcl/qa/cppunit/complextext.cxx(98) : error : Assertion
Test name: VclComplexTextTest::testArabic
equality assertion failed
- Expected: 72
- Actual  : 75

Failures !!!
Run: 3   Failure total: 1   Failures: 1   Errors: 0

Error: a unit test failed, please do one of:
make CppunitTest_vcl_complextext CPPUNITTRACE=TRUE # which is a shortcut for the following line
make CppunitTest_vcl_complextext CPPUNITTRACE="'C:/Program Files (x86)/Microsoft Visual 
Studio/2017/Community/Common7/IDE/devenv.exe' /debugexe" # for interactive debugging in Visual 
Studio
make CppunitTest_vcl_complextext CPPUNITTRACE="drmemory -free_max_frames 20" # for memory checking 
(install Dr.Memory first, and put it to your PATH)

You can limit the execution to just one particular test by:

[build DEP] LNK:CppunitTest/test_writerperfect_calc.dll
make CppunitTest_vcl_complextext CPPUNIT_TEST_NAME="testXYZ" ...above mentioned params...

[build LNK] CppunitTest/test_writerperfect_calc.dll
make[1]: *** [C:/core/solenv/gbuild/CppunitTest.mk:120: 
C:/core/workdir/CppunitTest/vcl_complextext.test] Error 1
make[1]: *** Waiting for unfinished jobs....
   Creating library C:/core/workdir/LinkTarget/CppunitTest/itest_xmloff_uxmloff.lib and object 
C:/core/workdir/LinkTarget/CppunitTest/itest_xmloff_uxmloff.exp
make: *** [Makefile:286: build] Error 2