do not assert on output of numeric 0 from a js handler

src/jsifier.js

@@ -536,7 +536,6 @@ function JSify(data, functionsOnly, givenFunctions) {
         case 'unreachable': line.JS = unreachableHandler(line); break;
         default: throw 'what is this line? ' + dump(line);
       }
-      assert(line.JS);
       //if (ASM_JS) assert(line.JS.indexOf('var ') < 0, dump(line));
       if (line.assignTo) makeAssign(line);
       Framework.currItem = null;

tests/cases/sub_11_0.ll

@@ -0,0 +1,16 @@
+; ModuleID = 'tests/hello_world.bc'
+
+@.str = private unnamed_addr constant [15 x i8] c"hello, world!\0A\00", align 1 ; [#uses=1 type=[15 x i8]*]
+
+; [#uses=0]
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4                   ; [#uses=1 type=i32*]
+  %0 = sub nsw i32 1, 1
+  store i32 %0, i32* %retval
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([15 x i8]* @.str, i32 0, i32 0)) ; [#uses=0 type=i32]
+  ret i32 1
+}
+
+; [#uses=1]
+declare i32 @printf(i8*, ...)