tests: Add tests to erase a chip

Two tests cover the code which performs do_erase operation.

First one works with fake chip and dummy programmer. Fake chip has all
operations defined, and a buffer to emulate chip memory.

Second one uses the chip which is closer to the real one, because
read/write/unlock/erase operations are real. The tests takes the
advantage of dummyflasher's capability of emulating a W25Q128.V chip.

BUG=b:181803212
TEST=builds and ninja test

Change-Id: I6f74bfe4e02244d24d6c837cc3d551251e7b4898
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/56501
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>

tests/meson.build

@@ -20,6 +20,7 @@ srcs = [
   'spi25.c',
   'init_shutdown.c',
   'layout.c',
+  'chip.c',
 ]
 
 mocks = [