Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-plugin-160620...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-plugin-160620-2' into staging

Testing and plugin updates

  - clear up dtc warnings
  - add support for --enable-tsan builds
  - re-enable shippable cross builds
  - serialise cirrus check steps
  - fix check-tcg plugin issues
  - add lockstep plugin

# gpg: Signature made Tue 16 Jun 2020 14:50:09 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-plugin-160620-2: (21 commits)
  plugins: new lockstep plugin for debugging TCG changes
  tests/tcg: ensure -cpu max also used for plugin run
  tests/tcg: build plugin list from contents of src directory
  cirrus.yml: serialise make check
  Revert ".shippable: temporaily disable some cross builds"
  tests: Disable select tests under TSan, which hit TSan issue.
  docs: Added details on TSan to testing.rst
  util: Added tsan annotate for thread name.
  include/qemu: Added tsan.h for annotations.
  tests/docker: Added docker build support for TSan.
  thread: add tsan annotations to QemuSpin
  translate-all: call qemu_spin_destroy for PageDesc
  tcg: call qemu_spin_destroy for tb->jmp_lock
  qht: call qemu_spin_destroy for head buckets
  cputlb: destroy CPUTLB with tlb_destroy
  thread: add qemu_spin_destroy
  cpu: convert queued work to a QSIMPLEQ
  configure: add --enable-tsan flag + fiber annotations for coroutine-ucontext
  Makefile: remove old compatibility gunks
  Makefile: dtc: update, build the libfdt target
  ...

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