Merge remote-tracking branch 'remotes/quic/tags/pull-hex-20210725' into staging

Merge remote-tracking branch 'remotes/quic/tags/pull-hex-20210725' into staging

The Hexagon target was silently failing the SIGSEGV test because
the signal handler was not called.

Patch 1/2 fixes the Hexagon target
Patch 2/2 drops include qemu.h from target/hexagon/op_helper.c

**** Changes in v2 ****
Drop changes to linux-test.c due to intermittent failures on riscv

# gpg: Signature made Sun 25 Jul 2021 22:39:38 BST
# gpg:                using RSA key 7B0244FB12DE4422
# gpg: Good signature from "Taylor Simpson (Rock on) <tsimpson@quicinc.com>" [undefined]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 3635 C788 CE62 B91F D4C5  9AB4 7B02 44FB 12DE 4422

* remotes/quic/tags/pull-hex-20210725:
  target/hexagon: Drop include of qemu.h
  Hexagon (target/hexagon) remove put_user_*/get_user_*

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>