All LLVM instructions are LLVM values, but in the case of terminator
instructions their value is meaningless, and we don't use them.

Bug swiftshader:10

Change-Id: I9eb71e1dcea2614cb810021dfbf3c8908a7e2510
Reviewed-on: https://swiftshader-review.googlesource.com/7355Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>