ARM: Fix the use of the ToBooleanStub when VFP3 is not available

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
===================================================================
--- src/arm/code-stubs-arm.cc	(revision 6957)
+++ src/arm/code-stubs-arm.cc	(working copy)
@@ -1296,6 +1296,9 @@
 // This stub does not handle the inlined cases (Smis, Booleans, undefined).
 // The stub returns zero for false, and a non-zero value for true.
 void ToBooleanStub::Generate(MacroAssembler* masm) {
+  // This stub uses VFP3 instructions.
+  ASSERT(CpuFeatures::IsEnabled(VFP3));
+
   Label false_result;
   Label not_heap_number;
   Register scratch = r9.is(tos_) ? r7 : r9;