32-bit client.file_io test fails setting rlimit

On Fedora 27:

158: Test command: /work/dr/git/build_x86_dbg_tests/bin32/drrun "-s" "90" "-quiet" "-debug" "-killpg" "-stderr_mask" "0xC" "-dumpcore_mask" "0" "-code_api" "-c" "/work/dr/git/build_x86_dbg_tests/suite/tests/bin/libclient.file_io.dll.so" "/work/dr/git/src/suite/tests/client-interface/file_io_data.txt" "--" "/work/dr/git/build_x86_dbg_tests/suite/tests/bin/client.file_io"
158: Test timeout computed to be: 1500
158: 0123456789
158: 01234
158: abcdefg
158: x
158: EOF
158: 
158: dummy_func is rx
158: writable_buf is rw
158: read_only_buf is r
158: dr_safe_read() check
158: DR_TRY_EXCEPT check
158: dr_safe_write() check
158: vfprintf check: 1234
158: Error: fail to set rlimit for RLIMIT_NOFILE with lower value
158: file separation check
158: float i/o test: 3.1416
158: done