Update the simd.js (14aa231 -> 248545e)

API Change:
e38d8a9 Add SIMD types load and store opertaions
90570b9 Add the SIMD types support into DataView interface.
fc7927f Handle negative zero in float32x4 and float64x2 signMask getter
Add SIMD test case (simd_test7) for negative zero handling.
Merge pull request #2815 from huningxin/incoming

Update SIMD.js polyfill and add test case for negative zero handling.