Reland "[snapshot] Temporarily enable --lazy-deserialization"

This is a reland of da6aab43
Original change's description:
> [snapshot] Temporarily enable --lazy-deserialization
> 
> Flip the flag for one day to determine impact and flush out bugs.
> Please add crashes and regressions to https://crbug.com/v8/6796.
> 
> Bug: v8:6624,v8:6796
> Change-Id: I8b0581c40d956e01f94e9098ff935fdd5af36156
> Reviewed-on: https://chromium-review.googlesource.com/651408
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#47893}

Bug: v8:6624, v8:6796
Change-Id: I7df43925ccb2e6c1d3455439690526b0e1a6a747
Reviewed-on: https://chromium-review.googlesource.com/660218Reviewed-by: Michael Hablich <hablich@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47952}

src/flag-definitions.h

@@ -927,7 +927,7 @@ DEFINE_INT(runtime_stats, 0,
 DEFINE_VALUE_IMPLICATION(runtime_call_stats, runtime_stats, 1)
 
 // snapshot-common.cc
-DEFINE_BOOL(lazy_deserialization, false,
+DEFINE_BOOL(lazy_deserialization, true,
             "Deserialize code lazily from the snapshot.")
 DEFINE_BOOL(trace_lazy_deserialization, false, "Trace lazy deserialization.")
 DEFINE_BOOL(profile_deserialization, false,