partcl now passing 4,089 spec tests

With the cleanup of several segfaults in parrot and some recent improvements to ::tcl::mathop, partcl is now passing over 4K of the official 8.5.6 test suite!

That leaves expr.test as the last big source of potentially passing tests that aren't being counted; 347 tests in that file pass before an error due to promotion to bigints causes the file to abort.

Special thanks to moritz for providing CPU cycles for testing.