This verifies all builders successfully uploaded builds for a new version that we tag here.
This prevents a problem like happend on 1.38.35, where the mac and windows bots "skipped" the hash that we tagged - they built the one before, and I guess were too slow, so they skipped to the next commit after it? Which is expected I guess, but surprises me a little. Anyhow, with this fix we should avoid such problems in the future.
Tags 1.38.36 to verify things work and get people a working version.
Also check some other basic things: check the version built reports the right one in emcc -v, and that multiple emsdk updates still work.
The non-git case was not well documented and not tested, and it was broken since we switched the build infrastructure.
In the git case, an update is to do a git pull. In the non-git case, it downloads a zip and unpacks it. The old build infra apparently had builds created for this; instead, I made it download it directly from github. Perhaps we should consider creating builds for this as well eventually?
Also add a test for this, so we never break it again.
Also fix the can_be_installed which was always broken it seems - it returns True for success or a string for error, but didn't check if the output is True.
Includes a test, which hacks up emsdk to make it think it's on 32-bit, and verifies the error and message.
Keep the basic workflow test (checking what a user would do to get started) in bash, but otherwise it's more convenient for most tests to be in python.
