Update Task destructor logic to conform to the standard

[ryanolson]

Using gcc, the if(m_coroutine != nullptr) could trigger a compilation failure if the coroutine was returning a std23::expected with an error message of:

 error: satisfaction of atomic constraint ... depends on itself

Possibly relating to: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99599

Another workaround was to use

if(static_cast<std::coroutine_handle<>>(m_coroutine) != nullptr) {

but since std::coroutine_handle provides an operator bool(), this is definitely the better way to go as seen by the cppreference.com examples.

[codecov]

Codecov Report

Merging #258 (26bae7d) into branch-23.01 (63deb9c) will increase coverage by 0.04%.
The diff coverage is 100.00%.

Additional details and impacted files

@@               Coverage Diff                @@
##           branch-23.01     #258      +/-   ##
================================================
+ Coverage         72.47%   72.52%   +0.04%     
================================================
  Files               376      376              
  Lines             12077    12082       +5     
  Branches            921      921              
================================================
+ Hits               8753     8762       +9     
+ Misses             3324     3320       -4     

Flag	Coverage Δ
cpp	69.35% <100.00%> (+0.04%)	⬆️
py	38.31% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cpp/mrc/include/mrc/coroutines/task.hpp	88.88% <100.00%> (ø)
cpp/mrc/src/internal/system/fiber_task_queue.cpp	67.50% <0.00%> (-2.50%)	⬇️
cpp/mrc/src/internal/system/partitions.cpp	78.94% <0.00%> (+0.75%)	⬆️
cpp/mrc/src/internal/resources/manager.cpp	91.66% <0.00%> (+1.04%)	⬆️
cpp/mrc/include/mrc/coroutines/ring_buffer.hpp	90.00% <0.00%> (+1.11%)	⬆️
cpp/mrc/src/internal/memory/host_resources.cpp	71.87% <0.00%> (+6.25%)	⬆️

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[ryanolson]

@gpucibot merge