Move APIs from AAudioTesting.h to AAudio.h

The APIs in AAudioTesting.h are public NDK. It makes more sense to have
them in AAudio.h.

Bug: 378909883
Test: atest AAudioTests
Flag: EXEMPT NDK
Change-Id: Ic14a9a48bb9590dd5f41f59a01921254e01818ac
2 files changed