[Driver][Clang] Add -nodefaultrtlibs (#219496)
On z/OS testing compiler-rt does not work with the -nodefaultlibs since
that option remove both the standard libraries like libc and the
compiler-rt library. On other platforms adding an argument like `-lc`
back to the command line in the test scripts works because the path for
libc (eg. `-L<path>`) hadn't been removed. On z/OS, the standard
libraries are located in data sets and you need to specify them by
complete name (eg. `<HLQ>.SCEELIB(CELQS003)`).
This is adding the option `-nodefaultrtlibs` so the compiler-rt tests
can remove just the compiler-rt libs from the link step.
