brokerd tests: a slow fake podman no longer fails the time-limit tests

The fake wrote each argument with its own printf. On a loaded machine
(titan, serving Ornith while the gate runs) the 300 ms limit fired while
`run` was still recording, and the `kill` call's lines landed inside
`run`'s: `a_tool_past_its_time_limit_is_killed_removed_and_failed`
failed about one run in five. The fake now writes each call to a file of
its own and appends it with one `cat` (bash's printf writes line by
line), and the two time-limit tests check the calls other than `run`,
which may be killed before it records itself. Test-only; 20 of 20 runs
pass, and both tests pass with a forced one-second start.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

crates/brokerd/tests/support/fake_podman.rs

@@ -37,7 +37,9 @@ impl Drop for Fake {
 
 impl Fake {
     /// A fake whose `run` does `run_body` (a shell fragment; `$D` is the fake's directory). Every
-    /// other command (`kill`, `rm`) is recorded and succeeds.
+    /// other command (`kill`, `rm`) is recorded and succeeds. Each call is written to a file
+    /// of its own and then appended by one `cat`, one write, so a `kill` made while a slow `run`
+    /// starts is never mixed into its lines (the shell's `printf` writes line by line).
     pub fn new(tag: &str, run_body: &str) -> Fake {
         let n = NEXT.fetch_add(1, Ordering::SeqCst);
         let dir = std::env::temp_dir().join(format!("bx-fp-{tag}-{}-{n}", std::process::id()));
@@ -45,7 +47,7 @@ impl Fake {
         std::fs::create_dir_all(&dir).unwrap();
         let script = dir.join("podman");
         let text = format!(
-            "#!/bin/sh\nD='{}'\nfor a in \"$@\"; do printf '%s\\n' \"$a\"; done >> \"$D/calls\"\necho --- >> \"$D/calls\"\n[ \"$1\" = run ] || exit 0\n{run_body}\n",
+            "#!/bin/sh\nD='{}'\nprintf '%s\\n' \"$@\" --- > \"$D/call.$$\"\ncat \"$D/call.$$\" >> \"$D/calls\"\nrm -f \"$D/call.$$\"\n[ \"$1\" = run ] || exit 0\n{run_body}\n",
             dir.display()
         );
         std::fs::write(&script, text).unwrap();
@@ -68,6 +70,14 @@ impl Fake {
         calls
     }
 
+    /// Every call but `run`, in order. A `run` killed at its time limit may not have recorded
+    /// itself yet, or may record itself after the `kill`, so time-limit tests check these.
+    pub fn calls_but_run(&self) -> Vec<Vec<String>> {
+        let mut calls = self.calls();
+        calls.retain(|call| call.first().map(String::as_str) != Some("run"));
+        calls
+    }
+
     /// What the last `run` read on standard input, if the body saved it to `$D/stdin`.
     pub fn stdin(&self) -> String {
         std::fs::read_to_string(self.dir.join("stdin")).unwrap_or_default()