….60.x backport) (#35335)

Backport of #35327 to v1.60.x.
---
Source:
https://github.com/grpc/grpc/blob/4f7ead2c7b7b82ad80799bbfa482184991dcd346/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
New repo: https://github.com/grpc/psm-interop
New path: `.kokoro/psm_interop_kokoro_lib.sh`

Ref grpc/psm-interop#16

Co-authored-by: Sergii Tkachenko <[email protected]>

…kport) (#35462)

Backport of #34877 to v1.60.x.
---
Fix: #34853

In order to make debugging easier, we have begun printing backtraces in
servers. However, this change has the unintended consequence of printing
errors to stderr by default, which may not be expected by some users.

This PR reverts the change. We recommend that users set up a logging
sink if they want to see errors. We will add this to our documentation
later.

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Change was created by the release automation script. See go/grpc-release