fix(test): drop the duplicate classify() guard and test the cnighswonger#356 merge left behind

conflict-shape.sh's additive resolution on the cnighswonger#356 merge kept both sides of
two hunks where cnighswonger#356 (cut from upstream, before cnighswonger#345 or cnighswonger#355 existed)
independently re-added content cnighswonger#345 had already added on this branch: a
second `if (typeof body !== "string") return null;` guard (with its own,
now-superseded comment) stacked dead beneath the one already in classify(),
and a second, byte-identical copy of the
"classify survives a probe that answers with a status code" test right after
it. Both were textually different insertions at the same conflict hunk (so
"additive" concatenated them) but semantically the same content twice.
Neither duplicate changed behaviour -- the second guard clause is
unreachable, and node:test does not refuse a duplicate case name -- so the
suite passed either way; kept once, as the recorded resolution for this file
already documents keeping ours' guard.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QFPGPPSYmx8NNGqbEsSpNc

Co-Authored-By: Claude <noreply@anthropic.com>

Author: codeslake

test/proxy-held-port.test.mjs

@@ -53,13 +53,6 @@ function classify(body) {
   // because this is a shared helper with a history of differently shaped probes,
   // and the answer to one is "that was a reply, not an outage", not a TypeError.
   if (typeof body !== "string") return null;
-  // A NUMBER IS NOT AN OUTAGE, AND MUST NOT BE A TypeError EITHER. Six of this
-  // file's seven probes resolve `ERR:${e.code}`; the seventh resolves a bare
-  // statusCode on success, and its caller filters out 200 and hands the rest
-  // here. Measured on CI Node 22: one 502 reached this line and the case died
-  // as `body.startsWith is not a function` — a crash where the answer is
-  // simply "that was a reply, not an outage".
-  if (typeof body !== "string") return null;
   if (!body.startsWith("ERR:")) return null;
   if (/"carrying"\s*:\s*"gap-relay"/.test(body)) return null;
   if (/"status"\s*:\s*"degraded"/.test(body)) return OUTAGE.DEGRADED;
@@ -236,19 +229,6 @@ describe("held port (CACHE_FIX_HOLD_PORT)", { concurrency: CONCURRENCY }, () =>
     assert.equal(readyBody(""), false);
   });
 
-  // THE SEVENTH PROBE RESOLVES A NUMBER. Six of this file's probes resolve
-  // `ERR:${e.code}`; the one at the forced-kill case resolves a bare statusCode
-  // on success, and its caller filters out 200 and hands the rest to classify().
-  // A 502 therefore reaches it as a Number. Pinned as a unit case because the
-  // path only opens when a non-200 is actually observed — CI Node 22 saw one and
-  // the case died as `body.startsWith is not a function`, three runners apart
-  // from where it was introduced.
-  it("classify survives a probe that answers with a status code", () => {
-    assert.equal(classify(502), null, "a status code is a reply, not an outage");
-    assert.equal(classify(200), null);
-    assert.equal(classify("ERR:ECONNREFUSED"), OUTAGE.REFUSED);
-    assert.equal(classify("ECONNRESET"), null, "no ERR: prefix means it is not ours to classify");
-  });
 // The default is declared in proxy/config.mjs and repeated in the launcher.
 // If they drift, an unset CACHE_FIX_PROXY_PORT binds one port while callers
 // dial the other.