orcarm: Fix flushing of icache when using dual map

On a codemem_dual_map setup, we need to also flush the PROT_EXEC alias.
4 jobs for fix_arm_flush in 2 minutes and 5 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #480997
debian sid

00:00:50

passed #481000
docker windows 1607
msys2

00:01:02

passed #480998
docker windows 1607
vs2017 amd64

00:01:14

passed #480999
docker windows 1607
vs2017 x86

00:01:09