... instead of generating text.  This will keep the tree in a consistent
state, as previously the references to uniform values where to
TVariable's whose declarations were removed.

Bug: angleproject:2461
Bug: angleproject:4889
Change-Id: I2ef3787dede371514a5f495f4cc8fc67ea45f451
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2815564
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>