apex: pass --align-file-size to signapk

APEX files are sized as 4K-aligned so that they can be passed to Guest
OS via block apexes.

Bug: 192991318
Test: check size of built APEX files
Test: atest--host apexer_test
Change-Id: I893595f11ded413bc68e8de5a90a164522898fa9
1 file changed