Desugar bitwise negation into XOR and kill all UnaryOp stuff.

src/runtime.js

Index: src/runtime.js
diff --git a/src/runtime.js b/src/runtime.js
index f1b4585d3bbd111ccd4ef777dc96ae7b0f8bc21b..5339570ef6ee6d8e42430765caf828d7d4efa64e 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -294,13 +294,6 @@ function BIT_XOR(y) {
 }
 
 
-// ECMA-262, section 11.4.8, page 48.
-function BIT_NOT() {
-  var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
-  return %NumberNot(x);
-}
-
-
 // ECMA-262, section 11.7.1, page 51.
 function SHL(y) {
   var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);