cpu: Get rid of the IsThreadSync StaticInst flag.

This flag was never set and only checked in one place. If it was set, it
would have triggered a panic there.

Change-Id: I934a0346837c66bae8ce06f50027003bfd47083d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33737
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
4 files changed