Revert of [heap] Preserve optimized code maps accross GCs. (patchset #1 id:1...

Revert of [heap] Preserve optimized code maps accross GCs. (patchset #1 id:1 of https://codereview.chromium.org/1430293002/ )

Reason for revert:
Janks finalization of full GC.

Original issue's description:
> [heap] Preserve optimized code maps accross GCs.
>
> This disables the eager flushing of optimized code maps during full GCs
> and instead treats entries in those tables weakly by default. Note that
> for now entries are removed when one of its components dies.
>
> R=mvstanton@chromium.org
>
> Committed: https://crrev.com/7a1377aab2ba4e2c9a7d422b51f645cbbaec10c7
> Cr-Commit-Position: refs/heads/master@{#32045}

TBR=mvstanton@chromium.org,mstarzinger@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1467213002

Cr-Commit-Position: refs/heads/master@{#32173}

src/flag-definitions.h

@@ -380,7 +380,7 @@ DEFINE_INT(stress_runs, 0, "number of stress runs")
 DEFINE_BOOL(lookup_sample_by_shared, true,
             "when picking a function to optimize, watch for shared function "
             "info, not JSFunction itself")
-DEFINE_BOOL(flush_optimized_code_cache, false,
+DEFINE_BOOL(flush_optimized_code_cache, true,
             "flushes the cache of optimized code for closures on every GC")
 DEFINE_BOOL(inline_construct, true, "inline constructor calls")
 DEFINE_BOOL(inline_arguments, true, "inline functions with arguments object")