My memory isn't good enough to remember all opcodes by number.

Enum string list stripped in release builds.

Change-Id: Ifa9b9585ee6294a26db5676a34f8ad9c90f527b8
Reviewed-on: https://swiftshader-review.googlesource.com/c/25551
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Tested-by: Ben Clayton <bclayton@google.com>