[zip] Remove ZipReader's HasMore() and related methods

Removed:
ZipReader::HasMore()
ZipReader::OpenCurrentEntryInZip()
ZipReader::AdvanceToNextEntry()
ZipReader::current_entry_info()
struct ZipReader::EntryInfo

These methods and struct are not used anymore.

BUG=chromium:1295127
TEST=autoninja -C out/Default zlib_unittests && out/Default/zlib_unittests

Change-Id: I8763c287f362dd1ea7125901a256702b29b6267d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3454223


Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/main@{#973315}
NOKEYCHECK=True
GitOrigin-RevId: 905679b37654552f1d83dad23c3bb5c843885572