Improve parser test for bug 52760 (close tags are being stripped).

Split out the test for bug 52760 from the test for bug 17663, which should
make it more clear what's going on.

Change-Id: Iec7133e919a4ef35b781c92197009d889a659fd9
Merge "Improve parser test for bug 52760 (close tags are being stripped)."