Revert of [simd.js] Disable SIMD polyfill.

test/simdjs/harness-adapt.js

Index: test/simdjs/harness-adapt.js
diff --git a/test/simdjs/harness-adapt.js b/test/simdjs/harness-adapt.js
index 4c140525e7f382b074b07298add8a42b619302a8..c90d6cc9d181f571307da929197076cd60a89e6d 100644
--- a/test/simdjs/harness-adapt.js
+++ b/test/simdjs/harness-adapt.js
@@ -21,9 +21,8 @@
   }
 };
 
-// To enable SIMD polyfill, load ecmascript_simd.js here and
-// add to resources in SimdJs.json as well as the script to
-// re-generate SimdJs.json.
+// TODO(bbudge): Drop when polyfill is not needed.
+load('ecmascript_simd.js');
 
 load('base.js');