[lmi] Irreproducible assertion failure in GUI test

[Greg Chicares]

I doubt we can do anything about this; I report it only FWIW in case it
ever occurs again:

/opt/lmi/bin[0]$wine ./wx_test --ash_nazg --data_path=/opt/lmi/data 
--pyx=only_new_pdf      
NOTE: starting the test suite
about_dialog_version: started
About dialog version string is "20180719T1706Z".
about_dialog_version: ERROR (Assertion failure: Expected license dialog was not 
shown. [file /opt/lmi/src/lmi/wx_test_about_version.cpp, line 239, in 
OnInvoked()].)

I'm quite sure I didn't move the mouse cursor: I always move it to the
top of the physical screen (an area reserved for xfce "panels", where no
application can ever write anything) before running a GUI test, and never
touch the trackball or keyboard until the test finishes.

I upgraded 'wine' a few days ago, but there's no failure with an archived
lmi release that used an earlier wx version:

/opt/lmi/bin[0]$pushd /opt/lmi/lmi-20180625T2141Z 
/opt/lmi/lmi-20180625T2141Z[0]$wine ./wx_test --ash_nazg 
--data_path=/opt/lmi/data --pyx=only_new_pdf
NOTE: starting the test suite
about_dialog_version: started
About dialog version string is "20180625T1131Z".
time=262ms (for about_dialog_version)
about_dialog_version: ok

Rerunning the test suite with current HEAD, I can't reproduce it:

/opt/lmi/lmi-20180625T2141Z[0]$popd
/opt/lmi/bin[0]$wine ./wx_test --ash_nazg --data_path=/opt/lmi/data 
--pyx=only_new_pdf       
NOTE: starting the test suite
about_dialog_version: started
About dialog version string is "20180719T1706Z".
time=232ms (for about_dialog_version)
about_dialog_version: ok
benchmark_census: started