tests/run-sysroot.sh: Avoid testing output that depends on LZMA support

tests/run-sysroot.sh: Avoid testing output that depends on LZMA support

run-sysroot.sh checks whether a backtrace generated by eu-stack contains
symbol names found in binaries under a test sysroot.  Two frames in
the backtrace contain symbol names that must be read from .gnu_debugdata.

However this section can only be read if elfutils was built with LZMA
support.  If not, then the symbol names will be absent from the
backtrace.

Test the eu-stack output with these 2 frames removed in order to prevent
a test failure when LZMA support is missing.

Signed-off-by: Aaron Merey <amerey@redhat.com>