fix flaky tfs test

[jesterhazy]

Description of changes:

• change test_tfs.py so fixture endpoint is not created in regions that should be skipped
• will fix canary test errors in regions where this test is not supposed to be run

Merge Checklist

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[codecov-io]

Codecov Report

Merging #536 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #536   +/-   ##
=======================================
  Coverage   92.77%   92.77%           
=======================================
  Files          71       71           
  Lines        5357     5357           
=======================================
  Hits         4970     4970           
  Misses        387      387

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[jesterhazy]

closing. merged this fix into #537.