itkNarrowBandImageFilterBaseTest read/write race with GetPixel() / SetPixel()

Running the itkNarrowBandImageFilterBaseTest test with TSan:

```
WARNING: ThreadSanitizer: data race (pid=71194)
Read of size 4 at 0x000102c13fac by thread T13:
#0 itk::NarrowBandImageFilterBase, itk::Image>::ThreadedApplyUpdate(double const&, itk::NarrowBandImageFilterBase, itk::Image>::ThreadRegionType const&, unsigned int) itkNarrowBandImageFilterBase.hxx:234 (ITKNarrowBandTestDriver:arm64+0x10004307c)
#1 itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)::operator()(unsigned long) const itkNarrowBandImageFilterBase.hxx:132 (ITKNarrowBandTestDriver:arm64+0x100053698)
#2 decltype(std::declval, itk::Image>::GenerateData()::'lambda0'(unsigned long)&>()(std::declval())) std::__1::__invoke[abi:ue170006], itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long>(itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long&&) invoke.h:340 (ITKNarrowBandTestDriver:arm64+0x1000535b4)
#3 void std::__1::__invoke_void_return_wrapper::__call[abi:ue170006], itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long>(itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long&&) invoke.h:415 (ITKNarrowBandTestDriver:arm64+0x1000534f0)
#4 std::__1::__function::__alloc_func, itk::Image>::GenerateData()::'lambda0'(unsigned long), std::__1::allocator, itk::Image>::GenerateData()::'lambda0'(unsigned long)>, void (unsigned long)>::operator()[abi:ue170006](unsigned long&&) function.h:193 (ITKNarrowBandTestDriver:arm64+0x10005348c)
#5 std::__1::__function::__func, itk::Image>::GenerateData()::'lambda0'(unsigned long), std::__1::allocator, itk::Image>::GenerateData()::'lambda0'(unsigned long)>, void (unsigned long)>::operator()(unsigned long&&) function.h:364 (ITKNarrowBandTestDriver:arm64+0x100051730)
#6 std::__1::__function::__value_func::operator()[abi:ue170006](unsigned long&&) const function.h:518 (ITKNarrowBandTestDriver:arm64+0x100e1b52c)
#7 std::__1::function::operator()(unsigned long) const function.h:1169 (ITKNarrowBandTestDriver:arm64+0x100e16324)
#8 itk::PoolMultiThreader::ParallelizeArray(unsigned long, unsigned long, std::__1::function, itk::ProcessObject*)::$_2::operator()(unsigned long, unsigned long) const itkPoolMultiThreader.cxx:178 (ITKNarrowBandTestDriver:arm64+0x100e8e374)

Previous write of size 4 at 0x000102c13fac by thread T15:
#0 itk::Image::SetPixel(itk::Index<2u> const&, float const&) itkImage.h:211 (ITKNarrowBandTestDriver:arm64+0x10005da60)
#1 itk::NarrowBandImageFilterBase, itk::Image>::ThreadedApplyUpdate(double const&, itk::NarrowBandImageFilterBase, itk::Image>::ThreadRegionType const&, unsigned int) itkNarrowBandImageFilterBase.hxx:239 (ITKNarrowBandTestDriver:arm64+0x1000431f0)
#2 itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)::operator()(unsigned long) const itkNarrowBandImageFilterBase.hxx:132 (ITKNarrowBandTestDriver:arm64+0x100053698)
#3 decltype(std::declval, itk::Image>::GenerateData()::'lambda0'(unsigned long)&>()(std::declval())) std::__1::__invoke[abi:ue170006], itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long>(itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long&&) invoke.h:340 (ITKNarrowBandTestDriver:arm64+0x1000535b4)
#4 void std::__1::__invoke_void_return_wrapper::__call[abi:ue170006], itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long>(itk::NarrowBandImageFilterBase, itk::Image>::GenerateData()::'lambda0'(unsigned long)&, unsigned long&&) invoke.h:415 (ITKNarrowBandTestDriver:arm64+0x1000534f0)
#5 std::__1::__function::__alloc_func, itk::Image>::GenerateData()::'lambda0'(unsigned long), std::__1::allocator, itk::Image>::GenerateData()::'lambda0'(unsigned long)>, void (unsigned long)>::operator()[abi:ue170006](unsigned long&&) function.h:193 (ITKNarrowBandTestDriver:arm64+0x10005348c)
#6 std::__1::__function::__func, itk::Image>::GenerateData()::'lambda0'(unsigned long), std::__1::allocator, itk::Image>::GenerateData()::'lambda0'(unsigned long)>, void (unsigned long)>::operator()(unsigned long&&) function.h:364 (ITKNarrowBandTestDriver:arm64+0x100051730)
#7 std::__1::__function::__value_func::operator()[abi:ue170006](unsigned long&&) const function.h:518 (ITKNarrowBandTestDriver:arm64+0x100e1b52c)
#8 std::__1::function::operator()(unsigned long) const function.h:1169 (ITKNarrowBandTestDriver:arm64+0x100e16324)
#9 itk::PoolMultiThreader::ParallelizeArray(unsigned long, unsigned long, std::__1::function, itk::ProcessObject*)::$_2::operator()(unsigned long, unsigned long) const itkPoolMultiThreader.cxx:178 (ITKNarrowBandTestDriver:arm64+0x100e8e374)

```

We see from the above that one thread is writing to 0x000102c13fac and another is simultaneously reading from the same address.

Here is the relevant code, NB the fire emojis:

```c++
template
void
NarrowBandImageFilterBase::ThreadedApplyUpdate(const TimeStepType & dt,
const ThreadRegionType & regionToProcess,
ThreadIdType threadId)
{
// const int INNER_MASK = 2;
constexpr signed char INNER_MASK = 2;

typename NarrowBandType::ConstIterator it;
typename OutputImageType::Pointer image = this->GetOutput();
typename OutputImageType::PixelType oldvalue;
typename OutputImageType::PixelType newvalue;
for (it = regionToProcess.first; it != regionToProcess.last; ++it)
{
oldvalue = image->GetPixel(it->m_Index);//READ 🔥🔥🔥🔥
newvalue = oldvalue + dt * it->m_Data;
// Check whether solution is out the inner band or not
m_TouchedForThread[threadId] =
(m_TouchedForThread[threadId] || (!(it->m_NodeState & INNER_MASK) && ((oldvalue > 0) != (newvalue > 0))));
image->SetPixel(it->m_Index, newvalue);//WRITE 🔥🔥🔥🔥
}
}
```

I don't know this code at all, but given the names `PoolMultiThreader::ParallelizeArray` and `ThreadedApplyUpdate` this looks like different threads are supposed to be dealing with different regions, but I'd guess perhaps the regions are overlapping?