[8.1.x] creating inbound stream beyond max_concurrent limit errors with #6936

[masaori335]

After #6936 (backporting #6364) on the 8.1.x branch, we faced a bunch of HTTP/2 errors.
It looks like the number of open streams becomes wrong on long-living connections and it's trigger of these errors.

HTTP/2 stream error code=0x07 recv headers creating inbound stream beyond max_concurrent limit
HTTP/2 stream error code=0x01 recv headers malformed request
HTTP/2 stream error code=0x07 refused to create new stream, because ua_session is in half_close state
HTTP/2 stream error code=0x05 recv data stream closed

When we revert the commit (cee4fcb), these errors are gone.

An odd thing is we don't see these errors on our 9.0.x deployment. (it's crashing frequently, though)
Is 8.1.x missing some commit which 9.0.x has?

[masaori335]

I opened PRs 1). revert cee4fcb and 2). disable openclose_h2. IMO, the misordering SSN/TXN close hook issue is a bug, but we can leave it on 8.1.0 and wait for 9.0.0 for the fix.