Crash parsing output from valgrind

When running valgrind on an application that has memory errors (conditional branches that use uninitialized values), Qt Creator crashes when parsing the XML output. See the attached backtrace.

Note that on Arch Linux, packages are compiled with _GLIBCXX_ASSERTIONS enabled. Since this appears to be crashing on an assert for an uninitialized optional, this may be silently skipped when GLIBCXX asserts aren't enabled.