Add Compat to vector_speedtest.jl

[IainNZ]

File is using Compat but it wasn't imported.

[codecov]

Codecov Report

Merging #1598 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #1598   +/-   ##
======================================
  Coverage    90.8%   90.8%           
======================================
  Files          28      28           
  Lines        3708    3708           
======================================
  Hits         3367    3367           
  Misses        341     341

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