upstream #977

Job	Run time
jruby-head	1m 14s
html5lib-tests	52s
ruby-head-valgrind (enable)	6m 54s
ruby-head (ubuntu, enable)	2m 56s
ruby-head-valgrind (disable)	5m 36s
ruby-head (ubuntu, disable)	1m 33s
truffleruby-head (--disable-system-libraries --disable-static)	3m 7s
ruby-head (windows, enable)	3m 55s
truffleruby-head (--disable-system-libraries --enable-static)	5m 11s
ruby-head (windows, disable)	11m 23s
truffleruby-head (--enable-system-libraries)	2m 43s
xmlsoft-head (ubuntu)	1m 41s
xmlsoft-head-valgrind	6m 21s
ruby-head (macos, enable)	32s
xmlsoft-head (windows)	9m 29s
ruby-head (macos, disable)	2m 45s
xmlsoft-head (macos)	1m 34s
	1h 7m 46s

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