Fix ARM build for gcc-4.6

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 82fa8ceaf318a043620d0c67255c4dc344ba97fe..c7a42ab7cb6d52a9882ab8114661ceb8db5827c7 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2424,7 +2424,6 @@ void BinaryOpStub::GenerateSmiCode(
   Register left = r1;
   Register right = r0;
   Register scratch1 = r7;
-  Register scratch2 = r9;
 
   // Perform combined smi check on both operands.
   __ orr(scratch1, left, Operand(right));
@@ -3110,7 +3109,6 @@ void TranscendentalCacheStub::Generate(MacroAssembler* masm) {
 
     Label no_update;
     Label skip_cache;
-    const Register heap_number_map = r5;
 
     // Call C function to calculate the result and update the cache.
     // Register r0 holds precalculated cache entry address; preserve