Apply addToSequence to blocks.

Clear generated code.
It contained 'var;' statements.

src/Silk-Tests.js

@@ -100,7 +100,6 @@ var sanitizedAssertion;
 return $core.withContext(function($ctx2) {
 //>>excludeEnd("ctx");
 sanitizedAssertion=$recv(aString)._replace_with_("\x5cs*","");
-sanitizedAssertion;
 return $recv((function(){
 //>>excludeStart("ctx", pragmas.excludeDebugContexts);
 return $core.withContext(function($ctx3) {

src/Silk.js

@@ -146,7 +146,6 @@ return nil;
 $2=$recv($recv(selector)._last()).__eq(":");
 if($core.assert($2)){
 useArg=true;
-useArg;
 selector=$recv(selector)._allButLast();
 selector;
 } else {