fix CHttpHeader::Parse() not handling last header line

While running the unit tests on win32 (which still crash sometimes) I noticed that the test for CHttpHeader failed. After investigation I realized that the code always skipped the last header line in CHttpHeader::Parse().

I'm sure there's a cleaner wayto fix this but I didn't have time to look into it in detail.

PS: The changes in the test method don't change the test or anything, they just improve the console output in case of an error. Before it printed out
```
expected: refstr.c_str()
```
instead of the actually expected value.