...as seen in UITest_calc_demo:

> ==1010== Invalid read of size 4
> ==1010==    at 0x58DA550: __pthread_mutex_unlock_usercnt (/usr/src/debug/glibc-2.24-33-ge9e69e4/nptl/pthread_mutex_unlock.c:39)
> ==1010==    by 0x58DA550: pthread_mutex_unlock (/usr/src/debug/glibc-2.24-33-ge9e69e4/nptl/pthread_mutex_unlock.c:324)
> ==1010==    by 0x1085FB42: __gthread_mutex_unlock(pthread_mutex_t*) (/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../include/c++/6.3.1/x86_64-redhat-linux/bits/gthr-default.h:778)
> ==1010==    by 0x10861414: std::mutex::unlock() (/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../include/c++/6.3.1/bits/std_mutex.h:121)
> ==1010==    by 0x10861901: std::unique_lock<std::mutex>::unlock() (/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../include/c++/6.3.1/bits/std_mutex.h:323)
> ==1010==    by 0x108604C6: std::unique_lock<std::mutex>::~unique_lock() (/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../include/c++/6.3.1/bits/std_mutex.h:232)
> ==1010==    by 0x1085FA5E: (anonymous namespace)::ExecuteWrapper::ExecuteActionHdl(Timer*) (/vcl/source/uitest/uno/uiobject_uno.cxx:103)
> ==1010==    by 0x1085EDE7: (anonymous namespace)::ExecuteWrapper::LinkStubExecuteActionHdl(void*, Timer*) (/vcl/source/uitest/uno/uiobject_uno.cxx:85)
> ==1010==    by 0x10715647: Link<Timer*, void>::Call(Timer*) const (/include/tools/link.hxx:84)
> ==1010==    by 0x107154A6: Timer::Invoke() (/vcl/source/app/timer.cxx:89)
> ==1010==    by 0x106D3841: ImplSchedulerData::Invoke() (/vcl/source/app/scheduler.cxx:46)
> ==1010==    by 0x106D3D28: Scheduler::ProcessTaskScheduling(bool) (/vcl/source/app/scheduler.cxx:159)
> ==1010==    by 0x107040EF: ImplYield(bool, bool, unsigned long) (/vcl/source/app/svapp.cxx:508)
> ==1010==    by 0x106FE9A7: Application::Yield() (/vcl/source/app/svapp.cxx:558)
> ==1010==    by 0x106FE92A: Application::Execute() (/vcl/source/app/svapp.cxx:458)
> ==1010==    by 0x513F498: desktop::Desktop::DoExecute() (/desktop/source/app/app.cxx:1354)
> ==1010==    by 0x5141660: desktop::Desktop::Main() (/desktop/source/app/app.cxx:1698)
> ==1010==    by 0x10711884: ImplSVMain() (/vcl/source/app/svmain.cxx:192)
> ==1010==    by 0x10713197: SVMain() (/vcl/source/app/svmain.cxx:230)
> ==1010==    by 0x51AEDF7: soffice_main (/desktop/source/app/sofficemain.cxx:166)
> ==1010==    by 0x40091C: sal_main (/desktop/source/app/main.c:48)
> ==1010==    by 0x4008F6: main (/desktop/source/app/main.c:47)
> ==1010==  Address 0x2ccca4e8 is 72 bytes inside a block of size 96 free'd
> ==1010==    at 0x4C2F21A: operator delete(void*) (/builddir/build/BUILD/valgrind-3.12.0/coregrind/m_replacemalloc/vg_replace_malloc.c:576)
> ==1010==    by 0x1085FA55: (anonymous namespace)::ExecuteWrapper::ExecuteActionHdl(Timer*) (/vcl/source/uitest/uno/uiobject_uno.cxx:102)
> ==1010==    by 0x1085EDE7: (anonymous namespace)::ExecuteWrapper::LinkStubExecuteActionHdl(void*, Timer*) (/vcl/source/uitest/uno/uiobject_uno.cxx:85)
> ==1010==    by 0x10715647: Link<Timer*, void>::Call(Timer*) const (/include/tools/link.hxx:84)
> ==1010==    by 0x107154A6: Timer::Invoke() (/vcl/source/app/timer.cxx:89)
> ==1010==    by 0x106D3841: ImplSchedulerData::Invoke() (/vcl/source/app/scheduler.cxx:46)
> ==1010==    by 0x106D3D28: Scheduler::ProcessTaskScheduling(bool) (/vcl/source/app/scheduler.cxx:159)
> ==1010==    by 0x107040EF: ImplYield(bool, bool, unsigned long) (/vcl/source/app/svapp.cxx:508)
> ==1010==    by 0x106FE9A7: Application::Yield() (/vcl/source/app/svapp.cxx:558)
> ==1010==    by 0x106FE92A: Application::Execute() (/vcl/source/app/svapp.cxx:458)
> ==1010==    by 0x513F498: desktop::Desktop::DoExecute() (/desktop/source/app/app.cxx:1354)
> ==1010==    by 0x5141660: desktop::Desktop::Main() (/desktop/source/app/app.cxx:1698)
> ==1010==    by 0x10711884: ImplSVMain() (/vcl/source/app/svmain.cxx:192)
> ==1010==    by 0x10713197: SVMain() (/vcl/source/app/svmain.cxx:230)
> ==1010==    by 0x51AEDF7: soffice_main (/desktop/source/app/sofficemain.cxx:166)
> ==1010==    by 0x40091C: sal_main (/desktop/source/app/main.c:48)
> ==1010==    by 0x4008F6: main (/desktop/source/app/main.c:47)

Change-Id: Ie95bf07f2fcd9420c9c24e6829272430895957a6