Most glibc tests that use mtrace to verify that there were no memory
leaks from the glibc facilities used in a given test depend on the
.out file of the previous test so that the mtrace test runs mtrace and
nothing else.
Two, however, have a single target combining mtrace with something
else. In the case of libio/tst-fopenloc.check, the test both compares
the output with an expected baseline and runs mtrace. In the case of
posix/tst-rxspencer-mem, the test is run (with different command line
from the main run) and then mtrace is run, from the same makefile
target.
This patch splits both of these tests up to use separate makefile
targets for each thing tested; in the tst-rxspencer case, a file
tst-rxspencer-noutf8.c is created that just includes tst-rxspencer.c,
as is usual for tests where the same code gets tested in different
compile-time or runtime configurations.