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/manual_home_test.py

@@ -29,8 +29,9 @@ operator's own $ME or a manual $H energizes it:
      the origin lies, never negative. With an offset the head at the stops
      is declared at minus it and jogs to the origin, dark, before $H
      answers, through the sender and through the port; the envelope starts
-     at the origin, and an out-of-range offset is clamped; a jog cancel
-     ends the move short of the origin and $H says where it stopped
+     at the origin (an out-of-range offset clamped is lens_home_test.c's,
+     gfhome_clamp_home_mm); a jog cancel ends the move short of the origin
+     and $H says where it stopped
   9. a controller that starts over a released gantry (the marker in the
      state directory) comes up locked and writes no current until $ME
   8. each provider reads its own offsets and no other's: with both pairs set,
@@ -426,15 +427,6 @@ def test_stop_block_offsets(s):
         r = refused(s, line)
         if r != "error:15":
             fail("[offsets] %s, behind the origin, got %r, not error:15" % (line, r))
-    s.set_mode("manual", "manual_home_x = -10.3\nmanual_home_y = 1e9\n")
-    if s.sender.send("$H", timeout=30.0) != "ok":
-        fail("[offsets] $H with out-of-range offsets was refused")
-    st = s.port.state()
-    if st["mpos"][0] != 0 or st["mpos"][1] != 0:
-        fail("[offsets] the head did not end at the origin: %r" % st["mpos"][:2])
-    d = declared(s)
-    if d is None or d[0] != 0 or abs(d[1] + 279.0) > 0.01:
-        fail("[offsets] a negative offset and an oversized one declared %r, not (0, -279)" % (d,))
     # The panel's Set home here: the port answers once the head has stopped,
     # and the sender's count stays exact.
     s.set_mode("manual", "manual_home_x = 12.5\nmanual_home_y = 8\n")
@@ -449,8 +441,8 @@ def test_stop_block_offsets(s):
         fail("[offsets] the sender got %d responses for the port's home" % (s.sender.count() - before))
     s.set_mode("manual")
     print("PASS [offsets]: a manual home declared (-12.5, -8) and jogged to the origin before $H "
-          "answered, dark under a modal M3; the envelope started at the origin; a negative offset "
-          "became 0 and an oversized one the axis travel; the port's home answered at the origin")
+          "answered, dark under a modal M3; the envelope started at the origin; the port's home "
+          "answered at the origin")
 
 
 def test_origin_jog_cancel(s):