generate valid code for segfaulting loads, not assignless aborts

src/jsifier.js

@@ -1331,11 +1331,11 @@ function JSify(data, functionsOnly, givenFunctions) {
     switch (impl) {
       case VAR_NATIVIZED: {
         if (isNumber(item.ident)) {
-          item.assignTo = null;
           // Direct read from a memory address; this may be an intentional segfault, if not, it is a bug in the source
           if (ASM_JS) {
-            return 'abort(' + item.ident + ')';
+            return asmCoercion('abort(' + item.ident + ')', 'i32');
           } else {
+            item.assignTo = null;
             return 'throw "fault on read from ' + item.ident + '";';
           }
         }

tests/test_core.py

@@ -5046,7 +5046,7 @@ The current type of b is: 9
     src = r'''
       int main () {
         *(volatile char *)0 = 0;
-        return 0;
+        return *(volatile char *)0;
       }
       '''
     self.do_run(src, 'fault on write to 0' if not Settings.ASM_JS else 'abort()')