tests: Add functional tests for HPPA machines

tests: Add functional tests for HPPA machines

Add quick firmware boot tests (less than 1sec) for the
B160L (32-bit) and C3700 (64-bit) HPPA machines:

  $ make check-functional-hppa
  ...
  4/4 qemu:func-quick+func-hppa / func-hppa-hppa_seabios    OK 0.22s 2 subtests passed

Remove the duplicated B160L test in qtest/boot-serial-test.c.

Suggested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250102100340.43014-3-philmd@linaro.org>