Write zeros to byte array output

Because we reuse the output array
between seprate dx invocations, we
must write zeros to array. Otherwise, we might
end up picking up the output from
previous invocation.

Dx had an assumption that a new output
array is always allocated, and it was
a performance optimization not to write
zeros out. That does not apply any more.

BUG=65363025
Test: ByteArrayAnnotatedOutputTest

Change-Id: I984076e8078f9ed977f10cacb9b1b135b1d6358e
(cherry picked from commit 1b955c44fcdb68735c6b667b199016b4e96d9f73)
2 files changed