Remove assert to enable indexless access chains
Remove assert to enable indexless access chains

Remove assert to accept OpAccessChain without indexes.

Change-Id: Ie57f60d6ac35198e7d7a1b75071fcd985dc1da18
Bug: b/161516333
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/54728
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Presubmit-Ready: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,google/swiftshader,google/swiftshader