Program interface queries for arrays should return an invalid index
value for indices with leading zeroes.

Program interface queries should return invalid locations for built-in
variables.

Bug: angleproject:3596
Test: KHR-GLES31.core.program_interface_query.*
Change-Id: I484ab6e21dbe0c8a984e135ac947c4583a3fbfa2
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2159646Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Tobin Ehlis <tobine@google.com>
Commit-Queue: Tim Van Patten <timvp@google.com>