Harnesses: the null-sink cases other tests prove leave

The grblHAL harnesses keep what only a running controller shows; the
cases a host unit test in grblHAL-glowforge proves, and the log and
reply wording, leave.

- laser_lifecycle_test: test_arm_waits_for_the_fans goes. laser_arm_test
  case A4 (grblHAL-glowforge) proves the fan grace stretching the arm's
  acknowledgment budget, on the same arm path. The docstring names it.
- xy_mode_test: case_x32, case_invalid and the log checks go; the
  default, x16 and the low tick stay. xy_scale_test holds each mode's
  tick and the not-a-mode parse.
- planner_blocks_test: one restart, at $398 1000; the 400 pass and the
  fresh-store probe go.
- ctlport_test: test_poll_lf and test_crlf go (the CR LF poll stays); in
  test_sender_out the network turn-away goes (serial_test holds it), and
  the busy gating, the grant and the outlives-client part stay.
  test_port_dark is whole.
- mcode_test: the timeout case runs on the host build's 5 s
  GFMCODE_WAIT_S (grblHAL-glowforge's CI configures it; the image keeps
  30 s) and still shows the hold, at 5.1 s; 5 s outlasts the 3 s
  test_dark watches the wait; test_table refuses one form per
  parser branch. test_timeout_holds and test_dark stay.
- envelope_test: test_unset and test_bounds go (lens_home_test holds the
  clamp); test_armed and the open, apply and close cases stay.
- manual_home_test: the out-of-range offset block goes, a repeat of
  gfhome_clamp_home_mm (lens_home_test); the modal-M3 FIRE check and
  every release and energize case stay.
- cool_report_test: one non-hex secret and one CR LF injection stay;
  runner-malformed and the exact header-set checks go. A bad secret is
  never sent and a good one is.
- tray_test: test_offset keeps 20 mm; test_errors keeps a bad P and a
  bad axis; the frame shift, envelope, barrier, persistence, port op,
  unreferenced lens and camera home stay.

Proof: with grblHAL-glowforge's matching commit, the eleven harnesses
its CI runs pass under Linux against the null-sink build: nine on a
build with a 1 s M-code wait, and mcode_test and tray_test, the two
that wait at an M-code, on the 5 s build CI configures
(-DGFMCODE_WAIT_S=5.0). pyflakes reports nothing in the nine changed
files.

Push this before grblHAL-glowforge's commit.

Acceptance: none; host harnesses only.

scripts/bench/planner_blocks_test.py

@@ -18,12 +18,10 @@ Runs the native grblHAL_glowforge binary in null-sink mode (no hardware,
 no root) and drives it over TCP, keeping one settings store across
 restarts:
 
-  1. a fresh store starts and reports its default $398
-  2. $398=400 is accepted and read back
-  3. the controller restarted on that store answers on the port, reports
-     400 blocks, and the status report shows a planner that deep
-  4. the same at $398=1000, the top of the range
-  5. a motion line runs to completion on the deep buffer
+  1. $398=1000, the top of the range, is accepted and read back
+  2. the controller restarted on that store answers on the port, reports
+     1000 blocks, and the status report shows a planner that deep
+  3. a motion line runs to completion on the deep buffer
 
 A controller that connects and never answers after the restart is the
 failure this harness exists for. Every exit kills the controller it
@@ -50,7 +48,6 @@ PORT = 2401
 CONNECT_S = 8.0
 ANSWER_S = 5.0
 
-DEEP = 400
 TOP = 1000
 
 _live = None            # the controller process a failure has to take down
@@ -199,15 +196,6 @@ def main():
         fail("no controller binary at %s" % BIN)
     workdir = tempfile.mkdtemp(prefix="planner-blocks-")
     try:
-        s = Session(workdir)
-        check(s.answers(), "a fresh store starts and answers",
-              "a fresh store does not answer")
-        print("     default $398=%s" % s.setting("$398"))
-        s.stop()
-
-        s = restart_on(workdir, DEEP)
-        s.stop()
-
         s = restart_on(workdir, TOP)
         reply = s.send("G91 G1 X1 F600", 1.5)
         check("ok" in reply and "error" not in reply and "ALARM" not in reply,
@@ -216,7 +204,7 @@ def main():
         check(s.wait_idle(), "the move completes and the controller is Idle",
               "the controller did not return to Idle after the move")
         s.stop()
-        print("PASS: the planner buffer starts at %d and %d blocks" % (DEEP, TOP))
+        print("PASS: the planner buffer starts at %d blocks" % TOP)
     finally:
         if _live is not None:
             _live.stop()