perf: remove some exception control flow and buffer-exception penalization for arrays

[cpcloud]

Remove some smaller overheads from kernel launch. These are pretty modest gains of between 5-8%, but they are reproducible.

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[greptile-apps]

Greptile Summary

This PR optimizes kernel launch overhead through cleaner code patterns that avoid exception handling:

• numpy_support.py: Replaces try/except KeyError with dict.get() and try/except AttributeError with getattr() using the walrus operator. These changes eliminate exception overhead while maintaining identical functionality.

• typeof.py: Reorders type checking to prioritize __cuda_array_interface__ before the buffer protocol check. This avoids expensive memoryview creation and exception handling for CuPy arrays and other CUDA-aware arrays.

Both changes follow the principle of avoiding exceptions for control flow, which is a Python performance best practice. The logic remains functionally equivalent with no behavioral changes.

Confidence Score: 5/5

• This PR is safe to merge with no identified risks
• The changes are pure performance optimizations that maintain identical behavior. Exception handling is replaced with standard Python idioms (.get(), getattr()), and type check reordering preserves logical correctness while improving efficiency for common cases (CuPy arrays). No functional changes or edge case issues identified.
• No files require special attention

Important Files Changed

Filename	Overview
numba_cuda/numba/cuda/np/numpy_support.py	Replaced exception-based control flow with dict.get() and getattr() for cleaner, faster lookups. Changes are safe and idiomatic.
numba_cuda/numba/cuda/typing/typeof.py	Moved buffer protocol check after __cuda_array_interface__ check to avoid expensive memoryview creation for CuPy arrays. Maintains correctness while improving performance.

[kkraus14]

/ok to test