tests/thirdparty: add segmentio/asm

[mmcloughlin]

Fixes #200

[codecov-commenter]

Codecov Report

Merging #201 (9b34f79) into master (8ff8e3b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #201   +/-   ##
=======================================
  Coverage   75.64%   75.64%           
=======================================
  Files          56       56           
  Lines       35091    35091           
=======================================
  Hits        26546    26546           
  Misses       8395     8395           
  Partials      150      150           

Flag	Coverage Δ
integration	8.75% <ø> (ø)
unittests	73.30% <ø> (ø)

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