This Cl clarifies that IntLiteral is a signed value, which matches with
the usage of UintLiteral.
Change-Id: Ic8f0e2382cb66eb6b09daed096886dcc55e6b0f0
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/22540
Reviewed-by: David Neto <dneto@google.com>
dan sinclair