[TRT EP] Fix multithreading bug of getting the corrupted trt engine instance (#17507)
Revert to the old TRT EP behavior of securing the whole compute_function
by lock_guard.
Current TRT EP which only puts lock_guard around a critical section
(obvious wrong) inside compute_function.
The issue can happen where one thread is updating the engine in
compute_function whereas another thread still accesses the
stale/corrupted engine instance in compute_function, for example, the
code outside the critical section, `int total_bindings =
trt_engine->getNbBindings()`.
So, make the whole compute_function the critical section should be okay.