Add 16.0.5 and 16.0.6 distributions

[adzenith]

I ran these commands:

utils/llvm_checksums.sh -g -v 16.0.4
utils/llvm_checksums.sh -g -v 16.0.5
utils/llvm_checksums.sh -g -v 16.0.6

and integrated the results into the distributions file. (I updated 16.0.4 because it looks like there are new distributions since this file was last updated).

[siddharthab]

Thanks!

[adzenith]

Thanks for the project, and for the fastest merge I've ever seen! :)