Add a test for zephyr,memory-region-flags.
This test tests the attributes of memory regions defined in the linker
script, but this information cannot be obtained at runtime.
It verifies that the expected memory region attributes are defined in
the linker.cmd.
Since no syntax analysis is performed, this is not an entirely rigorous
test but sufficient for practical purposes.
Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>
