test: remove per-test deadlines owned by project policy

Explicit deadlines at or below the project deadline only shortened it:
a literal 30-second value also disabled the coverage scaling, which timed
out wide-capacity regressions on main. Workloads above the built
deadline use the long-running tag. Deadlines derived from an operation
budget remain.

Co-Authored-By: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/process/ExecFileOutput.test.ts

@@ -207,7 +207,6 @@ describe("execFileOutput", () => {
         await execution;
       }
     },
-    10_000,
   );
 
   it.skipIf(process.platform === "win32")(
@@ -562,7 +561,7 @@ describe.skipIf(process.platform === "win32")(
         killFailure = await stopOwnedDescendant(pid, finished);
       }
       if (killFailure !== undefined) throw killFailure;
-    }, 15_000);
+    });
 
     it("keeps scratch files until an inherited-pipe descendant closes them", async () => {
       const directory = await createTestTempDirectory("rea-exec-inherited-");