h2 websockets backport for 2.4.x #420

Job	Run time
Empty APLOGNO() test	40s
Default	4m 25s
All-static modules	4m 1s
Prefork MPM, all-modules (except cgid)	5m 50s
Worker MPM, all-modules	4m 44s
Shared MPMs, all-modules	4m 41s
Event MPM, all-modules, mod_cgid only	5m 15s
Event MPM, all-modules, no CMSG_DATA	4m 30s
Default, all-modules + install	5m 36s
Default, all-modules, random test order	5m 34s
GCC 10 maintainer-mode w/-Werror, install + VPATH	4m 57s
All-modules, APR 1.7.4, APR-util 1.6.3	4m 36s
APR 1.8.x, APR-util 1.7.x	6m 50s
Pool-debug	7m 33s
Shared MPMs (event), pool-debug, SSL/TLS variants	12m 11s
Shared MPMs (worker), pool-debug, SSL/TLS variants	10m 23s
Shared MPMs (prefork), pool-debug, SSL/TLS variants	12m 36s
litmus WebDAV tests	2m 36s
APR 1.7.4, APR-util 1.6.3, LDAP	5m 24s
APR trunk thread debugging	5m 18s
ASan	9m 34s
ASan, pool-debug	9m 59s
HTTP/2 test suite	14m 28s
MOD_TLS test suite	7m 43s
	2h 39m 24s

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