Always sweep precisely.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/394023007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22476 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -516,7 +516,7 @@ DEFINE_BOOL(trace_incremental_marking, false,
             "trace progress of the incremental marking")
 DEFINE_BOOL(track_gc_object_stats, false,
             "track object counts and memory usage")
-DEFINE_BOOL(always_precise_sweeping, false, "always sweep precisely")
+DEFINE_BOOL(always_precise_sweeping, true, "always sweep precisely")
 DEFINE_BOOL(parallel_sweeping, false, "enable parallel sweeping")
 DEFINE_BOOL(concurrent_sweeping, true, "enable concurrent sweeping")
 DEFINE_INT(sweeper_threads, 0,