Add phi tests

[TensorCruncher]

Description

Unit test file for Phi adapter.

In light of the new guidelines for unit tests, I have made the following inclusions. Let me know if they need to be removed / changed:

1. Checking test_positional_embedding_type_is_rotary and test_parallel_attn_mlp_is_true. The prior is tested via component mapping and architecture guards, but since it is an override, I test it none the less. For the latter as well, it overrides a default, so it is tested despite having checks in component mapping (Parallel block bridge) and architecture guards (no ln2).

2. test_use_fast_is_false checks for attribute (assert adapter.cfg.use_fast is False) instead of checking dictionary in class definition. Is this acceptable?

3. Under component mapping, we check for explicitly set flags in the adapter: test_ln_final_use_native_layernorm_autograd_is_true,
   test_blocks_ln1_use_native_layernorm_autograd_is_true
test_attn_requires_attention_mask_is_true
test_attn_requires_position_embeddings_is_true

Related to #1302

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have not rewritten tests relating to key interfaces which would affect backward compatibility

[jlarson4]

@TensorCruncher Great work on this. The suite shape is right and the test coverage is good. Every category from the unit-test guide is represented, and the conversion/guard/setup-testing classes are exemplary. For the two flag tests you specifically flagged:

1. test_positional_embedding_type_is_rotary and test_parallel_attn_mlp_is_true are redundant. Their effects are already covered by your component-mapping tests (test_rotary_emb_is_rotary_embedding_bridge + test_no_pos_embed_component, test_blocks_is_parallel_block_bridge + test_no_ln2_in_blocks). Please delete both.
2. test_use_fast_is_false is fine to keep. It is a solid test and its effect isn't observable in the unit suite. Same for test_default_prepend_bos_is_false. The four explicit-kwarg tests under component mapping (use_native_layernorm_autograd, requires_attention_mask, requires_position_embeddings) are also fine.

[TensorCruncher]

I have removed the two redundant config literal tests. Thank you for your review and kind words!

[jlarson4]

You're welcome! Merging, it will be in the next release!