audioflinger and hal: Compatibility fixes for Treble

 1. Treat both reply size being 0 and reply buffer being NULL
    as an indication that the reply isn't needed.

 2. Synchronize both input and output effect chain buffers,
    and avoid excessive copies when the input buffer is the same as
    the output buffer.

 3. Improve effect chain debug dump by showing both
    "external" and "allocated" pointers for effect audio data buffers.

Bug: 34368451
Change-Id: I56aba6908408b5fce3f15c8d29138555101e8720
Test: volume controls works when both Bass Boost and EQ effects enabled