testsuite: Mark T24171 as fragile due to #24512

I will fix this but not in time for 9.10.1-alpha1

testsuite/tests/rts/linker/T24171/all.T

 test('T24171',
      [req_rts_linker,
       req_profiling,
-      extra_files(['Lib.hs', 'main.c'])],
+      extra_files(['Lib.hs', 'main.c']),
+      fragile(24512)],
      makefile_test,
      ['clean_build_and_run'])