Check which OpenMP for-loops could benefit from dynamic schedule

[mvieth]

          I guess other OMP implementations could use this setting as well, since most of those also require some search for neighbors, which can vary a lot and hence vary the computation between each iteration?

Originally posted by @larshg in #5775 (comment)

Candidates are for-loops where the loop iterations do not take the same time, e.g. when a neighbourhood search is done for each point in a cloud (especially radius search).
Files that contain parallelized for-loops and should be checked:

apps/3d_rec_framework/include/pcl/apps/3d_rec_framework/pipeline/impl/global_nn_recognizer_crh.hpp
apps/3d_rec_framework/include/pcl/apps/3d_rec_framework/pipeline/impl/local_recognizer.hpp
apps/3d_rec_framework/include/pcl/apps/3d_rec_framework/pipeline/impl/global_nn_recognizer_cvfh.hpp
common/src/range_image.cpp
common/src/fft/kiss_fft.c
features/include/pcl/features/impl/fpfh_omp.hpp
features/include/pcl/features/impl/shot_omp.hpp
features/include/pcl/features/impl/normal_3d_omp.hpp
features/include/pcl/features/impl/intensity_gradient.hpp
features/include/pcl/features/impl/shot_lrf_omp.hpp
features/src/range_image_border_extractor.cpp
features/src/narf.cpp
filters/include/pcl/filters/impl/convolution_3d.hpp
filters/include/pcl/filters/impl/convolution.hpp
filters/include/pcl/filters/impl/pyramid.hpp
filters/include/pcl/filters/impl/fast_bilateral_omp.hpp
filters/src/pyramid.cpp
io/include/pcl/io/impl/lzf_image_io.hpp
io/src/real_sense_2_grabber.cpp
keypoints/include/pcl/keypoints/impl/harris_6d.hpp
keypoints/include/pcl/keypoints/impl/trajkovic_3d.hpp
keypoints/include/pcl/keypoints/impl/iss_3d.hpp
keypoints/include/pcl/keypoints/impl/harris_3d.hpp
keypoints/include/pcl/keypoints/impl/harris_2d.hpp
keypoints/include/pcl/keypoints/impl/trajkovic_2d.hpp
keypoints/src/narf_keypoint.cpp
recognition/include/pcl/recognition/impl/hv/hv_go.hpp
registration/include/pcl/registration/impl/ia_fpcs.hpp
segmentation/include/pcl/segmentation/impl/approximate_progressive_morphological_filter.hpp
surface/include/pcl/surface/impl/mls.hpp
tools/fast_bilateral_filter.cpp
tools/normal_estimation.cpp
tracking/include/pcl/tracking/impl/pyramidal_klt.hpp
tracking/include/pcl/tracking/impl/kld_adaptive_particle_filter_omp.hpp
tracking/include/pcl/tracking/impl/particle_filter_omp.hpp