tests: add basic lifecycle test for ch341a_spi

TEST=the following scenarios run tests successfully

1) ch341a_spi is enabled
result: all tests run and pass, including ch341a

2) ch341a_spi is disabled
result: ch341a_spi test is skipped, the rest of tests run and pass

3) libusb isn't presented in the system
result: tests for usb programmers are skipped, the rest of tests run
normally

Change-Id: If28fbe09ad685082152aa3a7e8d5a150169aee9e
Signed-off-by: Alexander Goncharov <chat@joursoir.net>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67664
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>

meson.build

@@ -182,6 +182,7 @@ programmer = {
     'deps'    : [ libusb1 ],
     'groups'  : [ group_usb, group_external ],
     'srcs'    : files('ch341a_spi.c'),
+    'test_srcs' : files('tests/ch341a_spi.c'),
     'flags'   : [ '-DCONFIG_CH341A_SPI=1' ],
   },
   'dediprog' : {