Adding driver tests for proof of verification

[nmlud21]

Description

Resolves #4715

Adding driver tests to validate that production signed eBPF programs can be loaded, and that non-production-signed programs are correctly rejected. Pulling production signed binaries from 1es Azure storage blobs.

• Added positive and negative driver tests for proof of verification, one loads a production-signed driver (should succeed), the other loads a test-signed driver (should be rejected).
• Added a proof of verification registry toggle during test that allows for dynamically enabling/disabling production signature checks on native eBPF drivers, even when test signing is enabled, so CI tests can validate the signature verification path.
• Added CI infrastructure to provision signed binaries to 1es test runners, signed drivers are copied from the host into runners so the tests can find them at runtime.

Testing

This is adding a new test for proof of verification driver loading.

Documentation

None

Installation

None

[Alan-Jowett]

Minor nit for overall test hygiene: if any of the REQUIRE() assertions below this point fail, bpf_object__close(object) on line 3661 will never execute, leaking the loaded driver.

Other tests in this file already use the RAII pattern to avoid this (e.g. line 1926, 2350, 2505):

auto object_cleanup = std::unique_ptr<bpf_object, decltype(&bpf_object__close)>(object, bpf_object__close);

Would be nice to use the same pattern here so cleanup is guaranteed regardless of assertion outcomes.

[shankarseal]

Use EBPF_RETURN_RESULT

[nmlud21]

@shankarseal EBPF_RETURN_RESULT is not used in ebpf_store_helper.c Should all functions be updated to use this as well?