Moar test fixes

[kolyshkin]

The coverage job hit this on #684, which touches nothing but the cri-o test selection:

not ok 120 ctrl: rotate logs with --log-rotate
  in test file test/10-ctrl.bats, line 192
  `assert "${output}" =~ "before rotation"' failed

The race

ctrl: rotate logs with --log-rotate starts a container that writes before rotation, sends 2 1 1 to the control fifo to rotate the log, and then checks that the line is in the rotated file $LOG_PATH.1 and that what comes after is in the new $LOG_PATH.

The test waits for the container to be running before rotating, but that says nothing about conmon having written the first line to the log yet. Lose that race and the rotation moves a log that does not contain the line, before rotation lands in the fresh log along with after rotation, and $LOG_PATH.1 is there -- so the assert_file_exists above passes -- but empty. The coverage job is the slowest one, which is where this turns up.

So the test now waits for the line to be logged before rotating.

The helper

While adding the fourth "poll until X" helper to test_helper.bash, the loop -- deadline from $SECONDS, check, sleep, die -- was written out three times already. It is now

retry <how_long> <interval> <command ...>

which returns non-zero instead of dying: it does not know what it was waiting for, the callers do, and they keep their own messages. wait_for_runtime_status, wait_for_conmon_exit and wait_for_syncpipe_output are converted to it, and the new wait_for_log_line uses it too.

No functional change from the conversion, other than the status check in wait_for_runtime_status no longer printing expr's match count into the test log.

Ran the full suite locally: 120/120.

The unrelated CI breakage

Also here, since the cri-o job was red for a reason of its own: go 1.27 (which go-version: stable started resolving to) does not build cri-o main.

In golang.org/x/net v0.54.0, which cri-o vendors, http2 switches to a thin wrapper around net/http under go 1.27 (server.go is //go:build !(go1.27 && !http2legacy)), and http2.TrailerPrefix -- used by the vendored grpc -- is only defined in the non-wrapped build:

vendor/google.golang.org/grpc/internal/transport/handler_server.go:271:18: undefined: http2.TrailerPrefix

Upstream fixes this by vendoring x/net v0.55.0, which moves TrailerPrefix into a file built either way; see cri-o/cri-o#10103 (comment). Until that lands, go is pinned to 1.26 here.