The html package (aka x/net/html) through 2018-09-25 in Go mishandles <svg><template><desc><t><svg></template>, leading to a "panic: runtime error" (index out…

The html package (aka x/net/html) through 2018-09-25 in Go mishandles <svg><template><desc><t><svg></template>, leading to a "panic: runtime error" (index out of range) in (*nodeStack).pop in node.go, called from (*parser).clearActiveFormattingElements, during an html.Parse call.