Skip adjacency partitioning when the graph is fully supported

[micwill755]

Summary

• Skip adjacency partitioning when require_full_compilation already has full converter coverage, wrapping the graph as a single TRT block instead of repeating AccNodesFinder, fusion, and split.

This is PR 1/3 in a compile-startup stack:

1. This PR
2. Skip installing large aliased constant-folded weights #4528
3. Batch cheap FX cleanups and defer post_lowering recompile #4529

Test plan

• Compile a fully supported model with require_full_compilation=True and confirm one _run_on_acc_* submodule
• Compile a mixed-support graph and confirm adjacency partitioning still runs
• Flux / VLA compile still succeeds with this path enabled

[micwill755]

Superseded by the real GitHub stack (stack #4533): #4530 -> #4531 -> #4532. These fork branches could not be stacked because GitHub stacked PRs do not support pull requests from forks.