This is the "adoption agency" algorithm. The test case input is "<a><p>X<a>Y</a>Z</p></a>". The correct parse is: | <html> | <head> | <body> | <a> | <p> | <a> | "X" | <a> | "Y" | "Z" R=gri CC=golang-dev https://golang.org/cl/4771042
