Fix --trace-hydrogen --enable-slow-asserts combination.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index c14234f2bbc576818e1166d80005536920f7f648..6c2bdce26f9a2540adf5a66484d51103afc91628 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -1262,6 +1262,7 @@ CompilationPhase::~CompilationPhase() {
 bool CompilationPhase::ShouldProduceTraceOutput() const {
   // Trace if the appropriate trace flag is set and the phase name's first
   // character is in the FLAG_trace_phase command line parameter.
+  AllowHandleDereference allow_deref;
   bool tracing_on = info()->IsStub()
       ? FLAG_trace_hydrogen_stubs
       : (FLAG_trace_hydrogen &&