LU-12045 tests: honor EXCEPT tests when using ONLY list

LU-12045 tests: honor EXCEPT tests when using ONLY list

The Lustre test framework allows a user to specify a subset
of tests to run using the ONLY parameter or --only flag.
The test framwork also allows the user to specify a list of
tests to skip using the EXCEPT or ALWAYS_EXCEPT parameters.
By default, if the ONLY parameter or --only flag is used,
the EXCEPT and ALWAYS_EXCEPT lists are ignored.

Add a flag to auster, -H, and an environment variable,
HONOR_EXCEPT, to skip the tests on the ALWAYS_EXCEPT,
EXCEPT and SLOW lists when using the ONLY/--only parameter.

Lustre-commit: e636a709bf5948cd944ca9a42d4b74f07557a2ac
Lustre-change: https://review.whamcloud.com/34938

Test-Parameters: trivial
Test-Parameters: envdefinitions=ONLY="40-43" testlist=sanity
Test-Parameters: envdefinitions=ONLY="40-43" austeroptions=-H testlist=sanity
Test-Parameters: envdefinitions=SLOW="no",ONLY="27" testlist=sanity
Test-Parameters: envdefinitions=SLOW="no",ONLY="27" austeroptions=-H testlist=sanity
Test-Parameters: envdefinitions=SLOW="yes",ONLY="27" testlist=sanity
Test-Parameters: envdefinitions=SLOW="yes",ONLY="27" austeroptions=-H testlist=sanity
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I173e48e1d2dc3b404d148146639a13148bc48a3d
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/35901
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>