Merge remote-tracking branch...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-plugin-updates-180521-2' into staging

testing and plugin updates:

  - various fixes for binfmt_misc docker images
  - add hexagon check-tcg support docker image
  - add tricore check-tcg support
  - refactor ppc docker images
  - add missing ppc64le tests
  - don't use host_cc for test fallback
  - check-tcg configure.sh tweaks for cross compile/clang
  - fix some memory leaks in plugins

# gpg: Signature made Tue 18 May 2021 09:37:21 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-updates-180521-2: (29 commits)
  configure: use cc, not host_cc to set cross_cc for build arch
  tests/tcg: don't allow clang as a cross compiler
  tests/tcg: fix missing return
  tests/tcg/ppc64le: tests for brh/brw/brd
  tests/docker: gcc-10 based images for ppc64{,le} tests
  tests/tcg/tricore: Add muls test
  tests/tcg/tricore: Add msub test
  tests/tcg/tricore: Add madd test
  tests/tcg/tricore: Add ftoi test
  tests/tcg/tricore: Add fmul test
  tests/tcg/tricore: Add fadd test
  tests/tcg/tricore: Add dvstep test
  tests/tcg/tricore: Add clz test
  tests/tcg/tricore: Add bmerge test
  tests/tcg/tricore: Add macros to create tests and first test 'abs'
  configure: Emit HOST_CC to config-host.mak
  tests/tcg/tricore: Add build infrastructure
  hw/tricore: Add testdevice for tests in tests/tcg/
  tests/tcg: Run timeout cmds using --foreground
  tests/tcg: Add docker_as and docker_ld cmds
  ...

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