The team debated whether this was legal or not at the time.
It seems that at least one of Android's compilers generates code that stomps the list data after the `std::initializer_list` is declared and before it is used.

Switch to using regular C arrays with constexpr / std::array.

Fixes: b/149235682
Change-Id: Ief95dc4c6b4aee0c181bbe34aff19aa95f5fac8c
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/41051Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>