travis.yml: remove tests that overlap with Circle CI
travis.yml: remove tests that overlap with Circle CI

inikep/zstd,Majlen/zstd,ds77/zstd,Cyan4973/zstd,inikep/zstd,Cyan4973/zstd,Majlen/zstd,Cyan4973/zstd,inikep/zstd,ds77/zstd,Majlen/zstd,Cyan4973/zstd,Cyan4973/zstd,inikep/zstd,ds77/zstd,ds77/zstd,Majlen/zstd