Bug 1470732 - Add test case. r=tcampbell

js/src/jit-test/tests/basic/bug1470732.js

@@ -0,0 +1,12 @@
+if (helperThreadCount() === 0)
+    quit();
+
+var i = 0;
+while(i++ < 500) {
+  evalInWorker(`
+    assertFloat32(0x23456789 | 0, false);
+  `);
+  let m = parseModule("");
+  m.declarationInstantiation();
+}
+