Simplify and optimize ToBoolean handling.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
===================================================================
--- src/arm/lithium-arm.cc	(revision 8868)
+++ src/arm/lithium-arm.cc	(working copy)
@@ -1039,13 +1039,7 @@
         : instr->SecondSuccessor();
     return new LGoto(successor->block_id());
   }
-  LInstruction* branch = new LBranch(UseRegister(v));
-  // When we handle all cases, we never deopt, so we don't need to assign the
-  // environment then. Note that we map the "empty" case to the "all" case in
-  // the code generator.
-  ToBooleanStub::Types types = instr->expected_input_types();
-  bool all_cases_handled = types.IsAll() || types.IsEmpty();
-  return all_cases_handled ? branch : AssignEnvironment(branch);
+  return AssignEnvironment(new LBranch(UseRegister(v)));
 }