[Interpreter] Adds support for const/let variables to interpreter.

src/interpreter/bytecodes.h

Index: src/interpreter/bytecodes.h
diff --git a/src/interpreter/bytecodes.h b/src/interpreter/bytecodes.h
index aa5234924152f24a25383d980b2685749bd4d2db..2bcbef9cd26dd5ee5b505d0cd5e86db528c0cb73 100644
--- a/src/interpreter/bytecodes.h
+++ b/src/interpreter/bytecodes.h
@@ -235,6 +235,8 @@ namespace interpreter {
   V(JumpIfUndefined, OperandType::kImm8)                                       \
   V(JumpIfUndefinedConstant, OperandType::kIdx8)                               \
   V(JumpIfUndefinedConstantWide, OperandType::kIdx16)                          \
+  V(JumpIfHole, OperandType::kImm8)                                            \
+  V(JumpIfNotHole, OperandType::kImm8)                                         \

[rmcilroy, 2016/01/26 14:37:28]

It seems dangerous to have these without Constant and ConstantWide variants of
this Bytecode as well. I'm assuming these aren't needed now due to the way these
jumps are used, and it's probably not worth adding them if we are going to add
explicit assignment+throw bytecodes. If so, please add a TODO that these should
be removed once we have these bytecodes, or that we should add wide variants).

[mythria, 2016/02/01 10:02:18]

Done.

                                                                                \
   /* Complex flow control For..in */                                           \
   V(ForInPrepare, OperandType::kRegTriple8)                                    \
@@ -250,7 +252,6 @@ namespace interpreter {
   V(ReThrow, OperandType::kNone)                                               \
   V(Return, OperandType::kNone)
 
-
 // Enumeration of the size classes of operand types used by bytecodes.
 enum class OperandSize : uint8_t {
   kNone = 0,