Revert "[snapshot] Reduce serialization chunk size to 4K."

This reverts commit 2265a852.

Reason for revert:
https://ci.chromium.org/buildbot/client.v8.fyi/V8-Blink%20Linux%2064%20(dbg)/12451
https://test-results.appspot.com/data/layout_results/V8-Blink_Linux_64__dbg_/12451/layout-test-results/results.html


Original change's description:
> [snapshot] Reduce serialization chunk size to 4K.
> 
> This change may slow down deserialization of the snapshot but may result in less fragmentation.
> 
> Bug: v8:7887
> Change-Id: Id8bb9f1a561b08b7ae0f10b80aa77bc00eb23172
> Reviewed-on: https://chromium-review.googlesource.com/1125722
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Commit-Queue: Hannes Payer <hpayer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54198}

TBR=yangguo@chromium.org,hpayer@chromium.org

Change-Id: I3066426550f8c51de87fcf330a13aba5cebd7164
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7887
Reviewed-on: https://chromium-review.googlesource.com/1126219Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54212}

src/flag-definitions.h

@@ -1080,8 +1080,7 @@ DEFINE_BOOL(profile_deserialization, false,
             "Print the time it takes to deserialize the snapshot.")
 DEFINE_BOOL(serialization_statistics, false,
             "Collect statistics on serialized objects.")
-DEFINE_UINT(serialization_chunk_size, 4096,
-            "Custom size for serialization chunks")
+DEFINE_UINT(serialization_chunk_size, 0, "Custom size for serialization chunks")
 
 // Regexp
 DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")