Revert of [compiler] Enable shared function marking by default (patchset #1...

Revert of [compiler] Enable shared function marking by default (patchset #1 id:1 of https://codereview.chromium.org/2491773006/ )

Reason for revert:
Revert because it depends on https://codereview.chromium.org/2478323002/ which has been reverted.

Original issue's description:
> [compiler] Enable shared function marking by default
>
> BUG=v8:5512

TBR=bmeurer@chromium.org,leszeks@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5512

Review-Url: https://codereview.chromium.org/2491643006
Cr-Commit-Position: refs/heads/master@{#40926}

src/flag-definitions.h

@@ -269,7 +269,7 @@ DEFINE_BOOL(track_field_types, true, "track field types")
 DEFINE_IMPLICATION(track_field_types, track_fields)
 DEFINE_IMPLICATION(track_field_types, track_heap_object_fields)
 DEFINE_BOOL(smi_binop, true, "support smi representation in binary operations")
-DEFINE_BOOL(mark_shared_functions_for_tier_up, true,
+DEFINE_BOOL(mark_shared_functions_for_tier_up, false,
             "mark shared functions for tier up")
 
 // Flags for optimization types.