[x86/Linux] Enable CI unittest (#14442)

[x86/Linux] Enable CI unittest (#14442)

* [x86/Linux] Preparing pri2 unittest

- Copy test binary from x86 Windows build
- Copy CoreFX managed from arm CoreFX managed build
- Add archival

* Fix to merge test job generation

Change approach by expanding existing x64 & arm64 linux infrastructure

* [CI][Linux/x86] Fix configuration and architecture in netci.groovy

Fix to use configuration instead of lowerConfiguration
USe architecture and osGroup

* [CI][Linux/x86] Save test native builds in build job

Fix to save test native build in build job
Saved native builds are used on test job