[Release-testers] [9.0.0 Release] Release Candidate 4 is here

[Hans Wennborg via Release-testers]

Hello again,

9.0.0-rc4 was just tagged from the release_90 branch at r371490. In
the Git monorepo, it's tagged as llvmorg-9.0.0-rc4.

Source code and docs are available at
https://prereleases.llvm.org/9.0.0/#rc4 Binaries will be added as they
become available.

There are not a lot of changes from rc3 to rc4, and there are again no
open release blockers, so I'm hoping this will be the last release
candidate and that we can tag the final release soon.

Please file bug reports for any issues you find, marking them blocking
of https://llvm.org/PR42474

Release testers, please run the test script, share your results, and
upload binaries.

Thanks,
Hans