Fixed some memory leaks in Utility/Embed.c

Fixed __Pyx_sst_abs with C++11

Found by clang's static analyzer.
None of those are significant, but we might as well fix them.

Some compilers appear to require you to explicitly `#include <cstdlib>` before
providing `std::abs`.

deep-copy finally clauses of try-finally statements earlier to properly support arbitrary statements in them (genexprs, lambdas, etc.)

write XML results before printing test results to make it more likely that we get a test result dump also on later crashes or hangs

Do not search sys.path for .pxd file if no explicit "cimport" is given

cast PyUnicode_Tailmatch() "Py_ssize_t" result to int rather than propagating its type throughout the code base