[common/PyTorch] Add FusedAttention support for SWA (left, right)

[cyanguwa]

Description

This PR adds SWA (left, right) support to the FusedAttention backend for {bshd, sbhd, thd} formats and {no_mask, causal, causal_bottom_right, padding, padding_causal, padding_causal_bottom_right} masks.

Previously, the support was only for SWA (left, 0), {bshd, sbhd} formats, and {causal} mask.

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• 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)
• Infra/Build change
• Code refractor

Changes

Please list the changes introduced in this PR:

• Adds FusedAttention support for SWA (left, right)

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• 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

[cyanguwa]

/te-ci pytorch L0