[BEAM-1369] Reduce test times for two retry based tests

[sb2nov]

R: @charlesccychen PTAL

• The gcsio test was taking 2s so reducing the segment override makes it faster.
• The retry test now just starts at a lower time to speed it up from 1s -> 0.1s

Be sure to do all of the following to help us incorporate your contribution
quickly and easily:

• Make sure the PR title is formatted like:
  [BEAM-<Jira issue #>] Description of pull request
• Make sure tests pass via mvn clean verify. (Even better, enable
  Travis-CI on your fork and ensure the whole test matrix passes).
• Replace <Jira issue #> in the title with the actual Jira issue
  number, if there is one.
• If this contribution is large, please file an Apache
  Individual Contributor License Agreement.

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[coveralls]

Coverage increased (+0.003%) to 69.685% when pulling d6b9e55 on sb2nov:BEAM-reduce-test-times into b3d962d on apache:master.

[asfbot]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/beam_PreCommit_Java_MavenInstall/7095/
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[charlesccychen]

Thanks! LGTM.

[sb2nov]

@aaltay please merge