test: drop stale PASS/FAIL reference in host-harness loop comment

The per-test setjmp loop's doc comment still said it lands back in the
loop "to print PASS/FAIL and advance" — but child 1 (bf-52k2) and
child 2 (bf-344n) already replaced both branches' outcome labels with
the neutral RUN marker family ("RUN: <name>" / "RUN: <name>
(assertion failed)"). The comment now contradicts the code, so align
it with the "neutral marker line" phrasing already used lower in the
same block. No code change; gcc -std=c11 -Wall -Wextra still clean.

Co-Authored-By: Claude <noreply@anthropic.com>

firmware/test/test_runner.c

@@ -213,8 +213,9 @@ static int test_entry_cmp(const void *a, const void *b)
  *      on the direct call, so the body runs normally; if a failed assertion
  *      inside it calls test_record_failure(), that longjmp(g_test_jmp, 1)
  *      returns control here with setjmp yielding non-zero instead. Either way
- *      we land back in the loop to print PASS/FAIL and advance — a failure in
- *      test N never blocks tests N+1..end (the per-test setjmp/longjmp loop).
+ *      we land back in the loop to print a neutral RUN marker for the test and
+ *      advance — a failure in test N never blocks tests N+1..end (the per-test
+ *      setjmp/longjmp loop).
  *   3. Print a one-line run summary (passed / failed / total).
  *   4. Return 1 iff at least one test failed, else 0.
  *