VM: Remove unused IsClosureCall bit from IC data.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
===================================================================
--- runtime/vm/flow_graph_compiler.cc	(revision 39965)
+++ runtime/vm/flow_graph_compiler.cc	(working copy)
@@ -872,15 +872,6 @@
   uword label_address = 0;
   StubCode* stub_code = isolate()->stub_code();
   if (is_optimizing() && (ic_data.NumberOfUsedChecks() == 0)) {
-    if (ic_data.IsClosureCall()) {

[Florian Schneider, 2014/09/08 16:17:17]

This code has effectively become unreachable, because the IC miss handler always
enters a target (normal method, or a closure dispatcher method) into the IC data
the first time around.

So ic_data.NumberOfUsedChecks() is never zero for closure calls if they have
been executed before optimizing.

If they have not been executed before optimizing, IsClosureCall is naturally
false.

-      // This IC call may be closure call only.
-      label_address = stub_code->ClosureCallInlineCacheEntryPoint();
-      ExternalLabel target_label(label_address);
-      EmitInstanceCall(&target_label,
-                       ICData::ZoneHandle(ic_data.AsUnaryClassChecks()),
-                       argument_count, deopt_id, token_pos, locs);
-      return;
-    }
     // Emit IC call that will count and thus may need reoptimization at
     // function entry.
     ASSERT(!is_optimizing()