fix(ext/node): make zlib writeSync _writeState argument optional (#35185)

[tsushanth]

Closes #35185. Compat regression introduced by #35043.

#35043 moved the zlib write-result buffer (_writeState) from a pointer cached at handle init to a per-call argument on _handle.writeSync(...). The Rust op required it (#[buffer] write_result: &mut [u32]), so callers that bind directly to _handle.writeSync and never knew about per-call state — notably pngjs's sync-inflate.js, which is what png-to-ico (and the reporter's fount) pull in — now hit TypeError: expected typed ArrayBufferView when v8 sees undefined for the 8th slot. The high-level zlib.inflateSync / async PNG.parse() paths are unaffected because Deno's own zlib.js always passes the buffer.

This makes the per-call result buffer optional in the Inflate op signature:

• #[buffer] write_result: Option<&mut [u32]>
• the avail_out/avail_in write-back becomes if let Some(write_result) = write_result

When a caller does pass a state buffer (which Deno's polyfill, and any post-#35043 external code, does), the behavior is byte-for-byte identical — the security fix for the detached-buffer case is preserved because the per-call argument is still validated as a typed array. When a caller doesn't, the op just runs the inflate/deflate step without surfacing the post-write avail counts; the legacy contract for pngjs (which then reads its own bookkeeping) is restored.

Scope: the BrotliEncoder / BrotliDecoder / ZstdCompress / ZstdDecompress ops have the same write_result: &mut [u32] parameter, but I deliberately left them as-is. They postdate the pngjs era and we don't have an external caller report against them; the Inflate path is the one with a confirmed in-the-wild compat regression. Happy to widen the fix in a follow-up if the team prefers symmetry.

Tests

Added "zlib writeSync accepts the pre-#35043 seven-argument signature" in tests/unit_node/zlib_test.ts, mirroring the reporter's minimal repro: a zlib.createInflate() whose _handle.writeSync is invoked with seven arguments must not throw. Pre-fix this throws TypeError: expected typed ArrayBufferView; post-fix it returns successfully.

The detached-_writeState tests added by #35043 (writeSync does not write through a detached _writeState, writeSync populates _writeState per call) continue to pass since they exercise the eight-argument path that this PR doesn't change.

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