Updates to training pipelines to reduce CI time (#18116)
### Description
Motivation for this PR is reducing CI test time by removing unnecessary
tests from the pipelines.
Following changes are for reducing test time in pipelines:
- Skip CPU model tests in GPU builds. Training CIs run these tests as a
sanity check. There is no direct training code being tested in these
pipelines, furthermore, CPU tests are being run in CPU pipelines so no
need to run them again in GPU builds and block the GPU VM. This change
reduces testing time by 20-25 mins in all training GPU pipelines.
- Delete debug package building pipeline for linux training packages.
This was required by compiler team at some point but there have been 0
downloads of these packages.
### Motivation and Context
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