My previous work to integrate these tests was incomplete/incorrect, because I
misunderstood how the cmake macros worked.
This addresses items with the gtest tests, which in turn fixes test compilation
and adds more tests which I had previously missed.
Due to an unknown issue with gtest_stress_test, I had to add pthread to LIBADD,
even though I shouldn't have added it to that (it was failing to link -lpthread
to libprivategtest.a). Add a XXX comment to note that something's awry there
and deserves additional investigation.
The former is from googletest.test.mk, whereas the latter is from plain.test.mk.
As noted in r344328, Kyua will adopt more native GoogleTest support. Thus, it's
more desirable to make the test interface more of an opaque blackbox for the
testcase implementer.
