JavaScript: Add support for for-each-in comprehensions.

javascript/extractor/src/com/semmle/jcorn/CustomParser.java

@@ -274,16 +274,17 @@ public class CustomParser extends FlowParser {
 		List<ComprehensionBlock> blocks = new ArrayList<ComprehensionBlock>();
 		while (this.type == TokenType._for) {
 			SourceLocation blockStart = new SourceLocation(this.startLoc);
+			boolean of = false;
 			this.next();
+			if (this.eatContextual("each"))
+				of = true;
 			this.expect(TokenType.parenL);
 			Expression left = this.parseBindingAtom();
 			this.checkLVal(left, true, null);
-			boolean of;
 			if (this.eatContextual("of")) {
 				of = true;
 			} else {
 				this.expect(TokenType._in);
-				of = false;
 			}
 			Expression right = this.parseExpression(false, null);
 			this.expect(TokenType.parenR);

javascript/extractor/tests/mozilla/input/array_comprehensions.js

@@ -1,4 +1,5 @@
 [for (year of years) if (year > 2000) year];
 year;
 [for (i of numbers) for (j of letters) i+j];
-[for (i of numbers) for (j of letters) if (i<j) i+j];
+[for (i of numbers) for (j of letters) if (i<j) i+j];
+[for each (i in numbers) i];

javascript/extractor/tests/mozilla/input/generator_expressions.js

@@ -3,3 +3,4 @@ year;
 (for (i of numbers) for (j of letters) i+j);
 (for (i of numbers) for (j of letters) if (i<j) i+j);
 (x.p for (x in xs));
+(x.p for each (x in xs));