h2 websockets backport for 2.4.x #451

Job	Run time
Empty APLOGNO() test	29s
Default	5m 5s
All-static modules	4m 47s
Prefork MPM, all-modules (except cgid)	6m 29s
Worker MPM, all-modules	6m 11s
Shared MPMs, all-modules	6m 18s
Event MPM, all-modules, mod_cgid only	5m 26s
Event MPM, all-modules, no CMSG_DATA	5m 55s
Default, all-modules + install	4m 20s
Default, all-modules, random test order	5m 3s
GCC 10 maintainer-mode w/-Werror, install + VPATH	4m 31s
All-modules, APR 1.7.4, APR-util 1.6.3	5m 30s
APR 1.8.x, APR-util 1.7.x	8m 12s
Pool-debug	7m 47s
Shared MPMs (event), pool-debug, SSL/TLS variants	16m 52s
Shared MPMs (worker), pool-debug, SSL/TLS variants	18m 10s
Shared MPMs (prefork), pool-debug, SSL/TLS variants	21m 33s
litmus WebDAV tests	2m 41s
APR 1.7.4, APR-util 1.6.3, LDAP	4m 49s
APR trunk thread debugging	5m 51s
ASan	9m 21s
ASan, pool-debug	9m 33s
HTTP/2 test suite	14m 21s
MOD_TLS test suite	9m 17s
	3h 8m 31s

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