Clear all APF memory in testDropPingReply() in preparing stage

Modified testDropPingReply() to clear the entire APF memory instead of
only the first byte.  This addresses a known firmware issue with
handling programs smaller than 8 bytes.

Bug: 339147921
Test: TH
(cherry picked from https://android-review.googlesource.com/q/commit:e749694eb49fa74236d2388faeafd04c725fb461)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a6154578d261582be941f256c2eeeccd305aa65a)
Merged-In: I651dae8c9daac24b195196c03b54e69a757de8a7
Change-Id: I651dae8c9daac24b195196c03b54e69a757de8a7
1 file changed