VectorICs: turn on vectors for STORE and KEYED_STORE ics.

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1396523005

Cr-Commit-Position: refs/heads/master@{#31252}

src/flag-definitions.h

@@ -698,7 +698,7 @@ DEFINE_BOOL(use_idle_notification, true,
 // ic.cc
 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(vector_stores, true, "use vectors for store ics")
 DEFINE_BOOL(global_var_shortcuts, true, "use ic-less global loads and stores")
 
 // macro-assembler-ia32.cc