Add precompile statements

[odow]

Cherry-picked from #1264

Before

(base) oscar@Oscars-MBP scripts % '/Applications/Julia-1.6.app/Contents/Resources/julia/bin/julia' --project=. precompile.jl
 12.614850 seconds (43.66 M allocations: 2.490 GiB, 7.94% gc time, 23.81% compilation time)

After

(base) oscar@Oscars-MBP scripts % '/Applications/Julia-1.6.app/Contents/Resources/julia/bin/julia' --project=. precompile.jl
 10.383495 seconds (30.05 M allocations: 1.717 GiB, 5.08% gc time, 22.69% compilation time)

If you add #1264 with the improved inference, it drops to

(base) oscar@Oscars-MBP scripts % '/Applications/Julia-1.6.app/Contents/Resources/julia/bin/julia' --project=. precompile.jl
  8.106619 seconds (22.41 M allocations: 1.234 GiB, 5.04% gc time, 27.18% compilation time)