Ignore 32 bit ELFs in alignment checks

Some apps mixup 32 bit ELFs inside of arm64 directory.
Ignore 32 bit ELFs instead of erroring out.

PAGE_SIZE_APP_COMPAT_FLAG_UNDEFINED is equivalent of
skipping the current file. on return, flag is OR'ed
with flags from other ELF files. If some app has 32 bit ELF in
64 bit directory, alignment of that ELF will be ignored.

Flag: EXEMPT bug_fix
Test: atest -c FileSystemUtilsTests
Bug: 400741951
Change-Id: Ia9787f795bf9e84e194142f7d3e114daec1db722