Implement api test for aptx codecs

Test try to load the library and fail only if the library is present
with wrong api. (we allow a non-present library)
Second test is to call the method and check if they have the expected
behavior.

Bug: 226572369
Test: atest net_test_stack_a2dp_native
Ignore-AOSP-First: Aosp does not merge on tm
Change-Id: I495ad07696e229ae3a9a1122bede18fb1a5d62e2