CI: Tests on Xtensa simulator

[rascani]

Add CI running tests on Xtensa ISS simulator.

• Operator level tests executing on Xtensa ISS simulator
• Model level tests executing on Xtensa ISS simulator
• CI job running above operator & model tests
• Test results reported in CI dashboard

cc @mcremon-meta

[mcremon-meta]

cc @aliafzal. Nothing to do just yet, but this is on the horizon. @rascani, meet Ali who'll help us out on the OSS repo workstream (officially joining our team in a couple weeks, but ramping up already).

[cbilgin]

@mcremon-meta, @aliafzal, did we get a chance to take a look at this?

[aliafzal]

@cbilgin We have added CI for CPU based build and test, for specific backends requiring Xtensa ISS we are waiting to get secret license keys from cadence to run in CI

[rascani]

PR: #20208