Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-misc-080620-1...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-misc-080620-1' into staging

Various testing and misc fixes:

  - header cleanups for plugins
  - support wider watchpoints
  - tweaks for unreliable and broken CI
  - docker image fixes and verion bumps
  - linux-user guest_base fixes
  - remove flex/bison from various test images

# gpg: Signature made Mon 08 Jun 2020 17:16:19 BST
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-and-misc-080620-1:
  scripts/coverity-scan: Remove flex/bison packages
  cirrus-ci: Remove flex/bison packages
  tests/vm: Remove flex/bison packages
  tests/docker: Remove flex/bison packages
  linux-user: detect overflow of MAP_FIXED mmap
  tests/tcg: add simple commpage test case
  linux-user: deal with address wrap for ARM_COMMPAGE on 32 bit
  linux-user: provide fallback pgd_find_hole for bare chroots
  hw/virtio/vhost: re-factor vhost-section and allow DIRTY_MEMORY_CODE
  docker: update Ubuntu to 20.04
  tests/docker: fix pre-requisite for debian-tricore-cross
  .shippable: temporaily disable some cross builds
  .travis.yml: allow failure for unreliable hosts
  exec: flush the whole TLB if a watchpoint crosses a page boundary
  tests/plugin: correctly honour io_count
  scripts/clean-includes: Mark 'qemu/qemu-plugin.h' as special header
  qemu-plugin.h: add missing include <stddef.h> to define size_t

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