Remove CI builder customization from TEST

Remove CI builder customization from TEST

The default options are reasonable for all of the CI builders.

* TEST_XFSTESTS_SKIP=yes  - This is already the default.
* TEST_ZTEST_TIMEOUT=3600 - Increased ztest run time only increases
  code coverage by a small degree.  Default 900s runs are sufficient.
* Disabling certain tests on 32-bit builders is no longer needed.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10129