Cleanups.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 31957)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -34,9 +34,6 @@
             "Eliminate type checks when allowed by static type analysis.");
 DEFINE_FLAG(bool, print_ast, false, "Print abstract syntax tree.");
 DEFINE_FLAG(bool, print_scopes, false, "Print scopes of local variables.");
-DEFINE_FLAG(bool, print_flow_graph, false, "Print the IR flow graph.");
-DEFINE_FLAG(bool, print_flow_graph_optimized, false,
-            "Print the IR flow graph when optimizing.");
 DEFINE_FLAG(bool, trace_type_check_elimination, false,
             "Trace type check elimination at compile time.");
 DECLARE_FLAG(bool, enable_type_checks);