tests: update ANV skipped tests and modify help option

[crmurillo]

Description

This PR introduces two changes:

1. Removes the tests av1_superres_8bit and av1_frames_golden from the skipped list for ANV
   since they are now passing.

2. Groups the test framework help options into encoder and decoder sections for readability.

encoder options:
  --encoder ENCODER, -e ENCODER
                        Path to vk-video-enc-test executable
  --encoder-only        Run only encoder tests
  --encode-test-suite ENCODE_TEST_SUITE
                        Path to custom encode test suite JSON file
  --no-validate-with-decoder
                        Disable validation of encoder output with decoder (validation enabled by default)
  --decoder-args DECODER_ARGS [DECODER_ARGS ...]
                        Additional arguments to pass to decoder during encoder validation

decoder options:
  --decoder DECODER, -d DECODER
                        Path to vk-video-dec-test executable
  --decoder-only        Run only decoder tests
  --decode-test-suite DECODE_TEST_SUITE
                        Path to custom decode test suite JSON file
  --decode-display      Enable display output for decode tests (removes --noPresent from decoder commands)
  --no-verify-md5       Disable MD5 verification of decoded output (enabled by default when expected_output_md5 is preset)

Type of change

refactor

Tests

AMD Radeon RX 7600 (RADV NAVI33) / radv Mesa 26.1.0-devel (git-fa418f1e73) / Ubuntu 24.04.3 LTS

Total Tests: 70
Passed: 54
Crashed: 0
Failed: 0
Not Supported: 1
Skipped: 15 (in skip list)
Success Rate: 100.0%