Add checks to glDrawElementsInstanced, glGetShaderSource am: 6c667b4fb6 am: 0634b5f60b

Original change: https://googleplex-android-review.googlesource.com/c/device/generic/goldfish-opengl/+/11854593

Change-Id: I24ba1238bde33aaffe0d43084b919d0a89c83507