libmeminfo_test: Use vendor api level in the tests

ro.vendor.api_level property is provided for tests to check for the
API level supported by the device. Use it instead of the first_api_level.

Bug: 203839958
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I9338ab122d72b9f7011245a566318a500c20e878
2 files changed