Revert of Reland "Enable loads and stores to global vars through property cell...

Revert of Reland "Enable loads and stores to global vars through property cell shortcuts installed into paren… (patchset #1 id:1 of https://codereview.chromium.org/1237043006/)

Reason for revert:
chromium:510738, chromium:510911

Original issue's description:
> Reland "Enable loads and stores to global vars through property cell shortcuts installed into parent script context."
>
> Committed: https://crrev.com/48584df5ed97e2cdec1b4900f783c47adc3a3d32
> Cr-Commit-Position: refs/heads/master@{#29670}

TBR=verwaest@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1238163002

Cr-Commit-Position: refs/heads/master@{#29729}

src/flag-definitions.h

@@ -666,7 +666,7 @@ DEFINE_BOOL(use_idle_notification, true,
 DEFINE_BOOL(use_ic, true, "use inline caching")
 DEFINE_BOOL(trace_ic, false, "trace inline cache state transitions")
 DEFINE_BOOL(vector_stores, false, "use vectors for store ics")
-DEFINE_BOOL(global_var_shortcuts, true, "use ic-less global loads and stores")
+DEFINE_BOOL(global_var_shortcuts, false, "use ic-less global loads and stores")
 
 // macro-assembler-ia32.cc
 DEFINE_BOOL(native_code_counters, false,