Update levels in coeff optimization
Update levels in coeff optimization

When reducing the coefficient level gives better rate-distortion
results, update the the corresponding levels for next coefficient
context modeling.

Change-Id: Ia04e287a576f2a4afd1e8ecc9bcb311d067f02e5

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom