X87: [runtime] Use "the hole" instead of smi 0 as sentinel for context extension.

src/x87/macro-assembler-x87.h

Index: src/x87/macro-assembler-x87.h
diff --git a/src/x87/macro-assembler-x87.h b/src/x87/macro-assembler-x87.h
index c959ff25583b43a27bba14ae0332b5036fcf13e9..ecb40eea311c564458c07bd4e16d2c792155bb74 100644
--- a/src/x87/macro-assembler-x87.h
+++ b/src/x87/macro-assembler-x87.h
@@ -85,6 +85,12 @@ class MacroAssembler: public Assembler {
     CompareRoot(with, index);
     j(equal, if_equal, if_equal_distance);
   }
+  void JumpIfRoot(const Operand& with, Heap::RootListIndex index,
+                  Label* if_equal,
+                  Label::Distance if_equal_distance = Label::kNear) {
+    CompareRoot(with, index);
+    j(equal, if_equal, if_equal_distance);
+  }
 
   // Compare the object in a register to a value and jump if they are not equal.
   void JumpIfNotRoot(Register with, Heap::RootListIndex index,
@@ -93,6 +99,12 @@ class MacroAssembler: public Assembler {
     CompareRoot(with, index);
     j(not_equal, if_not_equal, if_not_equal_distance);
   }
+  void JumpIfNotRoot(const Operand& with, Heap::RootListIndex index,
+                     Label* if_not_equal,
+                     Label::Distance if_not_equal_distance = Label::kNear) {
+    CompareRoot(with, index);
+    j(not_equal, if_not_equal, if_not_equal_distance);
+  }
 
   // ---------------------------------------------------------------------------
   // GC Support