Disable a configuration broken upstream

ci/unittest.py

@@ -133,6 +133,13 @@ def run_linux_matrix():
                 "stdlib": "libc++",
                 "sanitizers": "ON",
             },
+            {
+                # disabled until https://github.com/davea42/libdwarf-code/issues/259 is fixed
+                "compiler": "g++-10",
+                "build_type": "RelWithDebInfo",
+                "split_dwarf": "ON",
+                "dwarf_version": "5",
+            },
         ]
     ).run(build_and_test)