Revert of Activate preserving of optimized code map accross GCs. (patchset #1...

Revert of Activate preserving of optimized code map accross GCs. (patchset #1 id:1 of https://codereview.chromium.org/1217863006/)

Reason for revert:
This CL may be the reason for the spike on memory corruption. Tentatively reverting this CL.

BUG=chromium:512780
LOG=n

Original issue's description:
> Activate preserving of optimized code map accross GCs.
>
> This enables --noflush-optimized-code-cache which allows preserving
> entries in the optimized code map accross GCs. This only applies to
> values being reachable through other paths.
>
> R=hpayer@chromium.org,hablich@chromium.org
>
> Committed: https://crrev.com/1a8776db25b63c4ce718423772d1fd13f58eeab5
> Cr-Commit-Position: refs/heads/master@{#29755}

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

Review URL: https://codereview.chromium.org/1255043003

Cr-Commit-Position: refs/heads/master@{#29888}

src/flag-definitions.h

@@ -366,7 +366,7 @@ DEFINE_BOOL(lookup_sample_by_shared, true,
             "when picking a function to optimize, watch for shared function "
             "info, not JSFunction itself")
 DEFINE_BOOL(cache_optimized_code, true, "cache optimized code for closures")
-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")