The new HTTP/2 protocol can be processed in a JMeter script using the Jmeter HTTP2 plugin however it does not work in Blazemeter tests.
Unfortunately the HTTP/2 protocol is not yet supported in Blazemeter as it requires special listeners that are not being used. However it is on the list to be implemented in the future. It is recommended to vote up the feature request already made by other customers: https://ideas.blazemeter.com/ideas/WAP-I-360 The more people vote for it, the more likely it is to be implemented in the not too distant future.
No real resolution as of yet. As a workaround you can run your test in the local JMeter and use the Blazemeter Uploader to upload the results to Blazemeter. Alternatively you can use the Taurus results loader to upload the results to a Blazemeter report.
Have a look at this blog on how to implement HTTP/2 in JMeter.
Currently the HTTP/2 sampler only works with Java 8 and requires the alpn-boot jar as explained in this article.