misc,tests: Remove support for GCC 5

Change-Id: I9d2e2958757d13330500fae555dde0abad58e23c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/47459
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
1 file changed