oeqa/selftest/glibc: Create selftest case for glibc test suite

oeqa/selftest/glibc: Create selftest case for glibc test suite

Create a oeqa selftest test case to execute the glibc test suite and
report the results. The results are populated into the extraresults
variable of the test case which are written to testresults.json for
resulttool to analyse.

An additional subclass is created to separate the execution with qemu
linux-user and qemu system. The GlibcSelfTestSystemEmulated test case
handles setup of the target image, setup of and NFS server as well as
execution with runqemu.

(From OE-Core rev: 730832ebcca305477e1c13248cd35eea095b35c6)

Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>