Disable tests failing on arm64

[scpeters]

🦟 Bug fix

Fixes #485 by disabling the failing portions of tests for arm64 architectures.

Summary

Some of the tests are failing that involve string comparisons of the output of stream operators with different levels of precision.

• 22.04 arm64: https://build.osrfoundation.org/job/gz-math7-debbuilder/904/
• 20.04 arm64: https://build.osrfoundation.org/job/gz-math7-debbuilder/906/

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #510 (ea80930) into gz-math7 (56d7985) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           gz-math7     #510   +/-   ##
=========================================
  Coverage     99.70%   99.70%           
=========================================
  Files            77       77           
  Lines          7007     7007           
=========================================
  Hits           6986     6986           
  Misses           21       21           

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[j-rivero]

Sorry to arrive a late. Although disabling the tests in other arches is the quickest way to have the software compiling I think it is not the best approach. For the two issues disabled here:

• The PI precision is best handled by applying the right precission (or making the software uniform across arches, if that is desired). See Added patch to deal with PI precission in arm64 gazebo-release/gz-math6-release#18
• The zero string comparison is a bit tedious to solve but best handled in https://github.com/gazebo-release/gz-math7-release/pull/18/files#diff-8f3eabaff9bb1ea079860addbc5396f22b0c887601af7c5e185c81b74ca18878 since it affects other non arm platforms.