Properly handle constant binding expressions

Previously, we would assign each binding expression a flag id even
if it is constant. This was necessary to be able to implement
invalidateAll.

Later, we've changed how invalidateAll works and assigned it a separate
flag. Unfortunately, we were still incrementing ids for such binding
expressions, causing index out of bounds exceptions during code generation
in certain situations.

This CL fixes that bug and does not add flags to constant binding expressions
anymore.
Bug: 21284295
Change-Id: I114bf34520d0b246426ce7d45b8c511cf6709778
9 files changed