test(cli): publish polled readiness files only when complete (#10563)

The doctor cancellation fixture wrote its readiness JSON with
writeFileSync, which truncates and then writes. The test polls only for
the file's existence, so a read between the two steps parsed an empty
file and failed with "Unexpected end of JSON input" (main run
43604752864, PR run 43606296871).

Write to a pending path and rename it into place, as ghidraJavaDoctor and
darwinProcessRunTokenReader fixtures already do. Apply the same fix to the
two sibling fixtures that poll for a PID file's existence and then parse
it: jadxConfiguration and runnerCancellation, where an empty read becomes
PID 0.

tests/boundary/android/jadxConfiguration.test.ts

@@ -508,7 +508,9 @@ const check = setInterval(() => {
   }
 }, 10);
 const watchdog = setTimeout(() => { process.exitCode = 99; clearInterval(check); }, 10000);
-fs.writeFileSync(ready, String(process.pid));
+// The test polls for this path; publish only the complete PID by renaming.
+fs.writeFileSync(ready + ".pending", String(process.pid));
+fs.renameSync(ready + ".pending", ready);
 `,
   );
   await chmod(java, 0o700);

tests/boundary/cli/doctorCancellation.test.ts

@@ -46,7 +46,9 @@ cliTest.skipIf(!["darwin", "linux"].includes(process.platform)).for(
       executable,
       `#!${process.execPath}
 if (!process.argv.slice(2).includes(${JSON.stringify(probeArgument)})) process.exit(7);
-require("node:fs").writeFileSync(${JSON.stringify(ready)}, JSON.stringify({pid: process.pid, runId: process.env.REA_PROCESS_RUN_ID, at: Date.now()}));
+// The test polls for this path; publish only complete JSON by renaming.
+require("node:fs").writeFileSync(${JSON.stringify(`${ready}.pending`)}, JSON.stringify({pid: process.pid, runId: process.env.REA_PROCESS_RUN_ID, at: Date.now()}));
+require("node:fs").renameSync(${JSON.stringify(`${ready}.pending`)}, ${JSON.stringify(ready)});
 process.on("SIGTERM", () => {});
 setInterval(() => { if (require("node:fs").existsSync(${JSON.stringify(release)})) process.exit(0); }, 25).unref();
 setTimeout(() => process.exit(99), 20000);

tests/process-global/runnerCancellation.test.ts

@@ -51,7 +51,9 @@ it.runIf(process.platform !== "win32")(
       const fs = require("node:fs");
       process.on("SIGTERM", () => {});
       fs.writeFileSync(${JSON.stringify(activityPath)}, "active\\n");
-      fs.writeFileSync(${JSON.stringify(pidPath)}, String(process.pid));
+      // The runner polls for this path; publish only the complete PID by renaming.
+      fs.writeFileSync(${JSON.stringify(`${pidPath}.pending`)}, String(process.pid));
+      fs.renameSync(${JSON.stringify(`${pidPath}.pending`)}, ${JSON.stringify(pidPath)});
       setInterval(() => fs.appendFileSync(${JSON.stringify(activityPath)}, "active\\n"), 20);
     `;
     const runner = launch(