[FIX] fix the bug of missing points

[gillbam]

Fix issue #406 :

• "break" leads to points missing during voxelization;
• "continue" ensures the completeness of voxelization

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #423 (10297c7) into master (ecd0d06) will not change coverage.
The diff coverage is 0.00%.

❗ Current head 10297c7 differs from pull request most recent head 9714872. Consider uploading reports for the commit 9714872 to get more accurate results

@@           Coverage Diff           @@
##           master     #423   +/-   ##
=======================================
  Coverage   50.25%   50.25%           
=======================================
  Files         183      183           
  Lines       13142    13142           
  Branches     2090     2090           
=======================================
  Hits         6605     6605           
  Misses       6103     6103           
  Partials      434      434           

Flag	Coverage Δ
unittests	50.25% <0.00%> (ø)

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Impacted Files	Coverage Δ
mmdet3d/core/voxel/voxel_generator.py	39.49% <0.00%> (ø)

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[ZwwWayne]

Hi @gillbam ,
Thanks for your kind contribution. Is the performance of models have been verified?

[hjin2902]

SECOND kitti 3 classes mAP:

• master: 66.59 (35 epoch, total 40 epoch)
• continue-pr: 66.39 (35 epoch, total 40 epoch)

SECOND kitti car AP:

• master: 78.32 (40 epoch)
• continue-pr: 78.15 (40 epoch)

[OpenMMLab-Assistant-007]

Hi!
@gillbam
First of all, we want to express our gratitude for your significant PR in the OpenMMLab project. Your contribution is highly appreciated, and we are grateful for your efforts in helping improve this open-source project during your personal time. We believe that many developers will benefit from your PR.

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