aaudio: loopback test improved

Check to make sure input capacity is large enough.
Add -B option to set input capacity.
Handles variable callback size better when setting up the
loop for Legacy mode.
Narrower impulse.

Bug: 80230720
Test: this is a test
Change-Id: I9349cf8248b65850073bfb8178bbb802a93fd684
3 files changed