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/tray_test.py

@@ -21,8 +21,8 @@ sender on the Grbl socket, and the port client of ctlport_test.py:
      the lens's reach, shifted, run and two half-steps past them are
      refused, and a jog to a tray-in Z is refused; with the tray in again
      the same jog runs
-  3. a missing P, a P other than 0 or 1, and an axis word on the line are
-     errors (28, 39, 31) that change nothing
+  3. a P other than 0 or 1, and an axis word on the line, are errors (39,
+     31) that change nothing
   4. the M-code is a barrier: behind a move it waits for the move to end,
      and the frame changes only once the machine is idle
   5. the port's tray op switches the mode with a sender connected, the
@@ -33,7 +33,7 @@ sender on the Grbl socket, and the port client of ctlport_test.py:
   6. the mode survives a soft reset, and a controller restart: a start with
      the marker present takes the lens reference in the tray-out frame,
      and one without it in the tray-in frame
-  7. tray_offset_mm sets the shift, held to 13 to 60 mm
+  7. tray_offset_mm sets the shift
   8. an unreferenced lens shifts the same way, and stays pinned where it
      reads
   9. a camera home with the tray out declares Z the offset higher, and
@@ -259,8 +259,7 @@ def test_envelope(s):
 
 def test_errors(s):
     ticks = s.ticks()
-    for line, want in (("M103", "error:28"), ("M103 P2", "error:39"), ("M103 P0.5", "error:39"),
-                       ("M103 P-1", "error:39"), ("M103 P1 Z5", "error:31"), ("M103 P1 X5", "error:31")):
+    for line, want in (("M103 P2", "error:39"), ("M103 P1 X5", "error:31")):
         r = refused(s, line)
         if r != want:
             fail("[errors] %r got %r, not %s" % (line, r, want))
@@ -270,7 +269,7 @@ def test_errors(s):
     time.sleep(0.3)
     if s.ticks() != ticks:
         fail("[errors] the refused lines shipped %d step ticks" % (s.ticks() - ticks))
-    print("PASS [errors]: a missing P, P2, P0.5, P-1 and an axis word were refused and changed nothing")
+    print("PASS [errors]: P2 and an axis word were refused and changed nothing")
 
 
 def test_barrier(s):
@@ -391,7 +390,7 @@ def test_persistence(s):
 
 
 def test_offset():
-    for key, k in (("20", 58), ("5", 38), ("99", 175)):
+    for key, k in (("20", 58),):
         s = Session(conf={"tray_offset_mm": key})
         try:
             s.sender.send("M103 P1")
@@ -400,8 +399,7 @@ def test_offset():
             expect_z(s, EDGE_K, "offset %s: back in" % key)
         finally:
             s.close()
-    print("PASS [offset]: tray_offset_mm 20 moved Z 58 half-steps, 5 was held to 13 mm (38), "
-          "99 to 60 mm (175)")
+    print("PASS [offset]: tray_offset_mm 20 moved Z 58 half-steps")
 
 
 def test_unreferenced():