Merge remote-tracking branch 'remotes/stsquad/tags/pull-fixes-for-rc2-270720-1' into...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-fixes-for-rc2-270720-1' into staging

Various fixes for rc2:

  - get shippable working again
  - semihosting bug fixes
  - tweak tb-size handling for low memory machines
  - i386 compound literal float fix
  - linux-user MAP_FIXED->MAP_NOREPLACE on fallback
  - docker binfmt_misc fixes
  - linux-user nanosleep fix
  - tests/vm drain console fixes

# gpg: Signature made Mon 27 Jul 2020 09:45:31 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-fixes-for-rc2-270720-1:
  tests/vm: add shutdown timeout in basevm.py
  python/qemu: Change ConsoleSocket to optionally drain socket.
  python/qemu: Cleanup changes to ConsoleSocket
  linux-user, ppc: fix clock_nanosleep() for linux-user-ppc
  linux-user: fix clock_nanosleep()
  tests/docker: add support for DEB_KEYRING
  tests/docker: fix binfmt_misc image building
  tests/docker: fix update command due to python3 str/bytes distinction
  linux-user: don't use MAP_FIXED in pgd_find_hole_fallback
  target/i386: floatx80: avoid compound literals in static initializers
  accel/tcg: better handle memory constrained systems
  util/oslib-win32: add qemu_get_host_physmem implementation
  util: add qemu_get_host_physmem utility function
  semihosting: don't send the trailing '\0'
  semihosting: defer connect_chardevs a little more to use serialx
  shippable: add one more qemu to registry url

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