scripts: gen_handles: Sort the device handles

Replicate the devicetree dependencies into a sorted list. This ensures
that the structures added to the .__device_handles_pass2 section are
reproducible from build to build.

Tested with: west build -b native_posix tests/drivers/build_all/sensor

Without this change, two consecutive builds do not compare.

Signed-off-by: Keith Short <keithshort@google.com>