[DO NOT MERGE] AMR WB encoder: prevent OOB write in ACELP_4t64_fx

In ACELP_4t64_fx, when iterating over ind array, check index against
  array size to prevent OOB write, log an error if such an access
  was about to happen.

Bug 132647222
Test: atest EncoderTest#testAMRWBEncoders
Merged-in: I33f476d94baec2feffc7bcccd0ad0481b8452518

Change-Id: I814a05217f20ea3b941deddb70edb31cd342de6b