Add asserts to ensure that we:

src/arm/deoptimizer-arm.cc

Index: src/arm/deoptimizer-arm.cc
===================================================================
--- src/arm/deoptimizer-arm.cc	(revision 9277)
+++ src/arm/deoptimizer-arm.cc	(working copy)
@@ -632,7 +632,10 @@
   __ mov(r5, Operand(ExternalReference::isolate_address()));
   __ str(r5, MemOperand(sp, 1 * kPointerSize));  // Isolate.
   // Call Deoptimizer::New().
-  __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate), 6);
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate), 6);
+  }
 
   // Preserve "deoptimizer" object in register r0 and get the input
   // frame descriptor pointer to r1 (deoptimizer->input_);
@@ -686,8 +689,11 @@
   // r0: deoptimizer object; r1: scratch.
   __ PrepareCallCFunction(1, r1);
   // Call Deoptimizer::ComputeOutputFrames().
-  __ CallCFunction(
-      ExternalReference::compute_output_frames_function(isolate), 1);
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(
+        ExternalReference::compute_output_frames_function(isolate), 1);
+  }
   __ pop(r0);  // Restore deoptimizer object (class Deoptimizer).
 
   // Replace the current (input) frame with the output frames.