Fix the size mismatch in imgdiff

As we construct the deflate entries of the target zip file with
random data, the total size of the zip file may vary from case
to case. This leads to occasional failures in the split test for
deflate large apk files. This CL fixes the issue by adding two static
zip files in the testdata instead of generating them dynamically.

Bug: 67849209
Test: run the deflate_large_test repeatedly
Change-Id: Iaeffad9205adefa10c9f62f9f088c33c4360a650