ignore_nested tests fail if dependencies are in non-standard directory

• capnp built from source and installed -> /usr/local/lib
• export LD_LIBRARY_PATH=/usr/local/lib
• other tests run, but these two don't:

test 958
    Start 958: ignore_nested

958: Test command: /usr/bin/bash "source_dir/src/test/ignore_nested.run" "ignore_nested" "" "bin_dir" "120"
958: Test timeout computed to be: 10000000
958: Test 'ignore_nested' FAILED: : error during recording:
958: --------------------------------------------------
958: /home/opc/rr/build/bin/rr: error while loading shared libraries: libcapnp-0.10.3.so: cannot open shared object file: No such file or directory
958: --------------------------------------------------
958: record.out:
958: --------------------------------------------------
958: --------------------------------------------------
958: Test ignore_nested failed, leaving behind /tmp/rr-test-ignore_nested-NziQHtT7g
958: To replay the failed test, run
958:   _RR_TRACE_DIR=/tmp/rr-test-ignore_nested-NziQHtT7g rr replay
1/2 Test #958: ignore_nested ....................***Failed  Error regular expression found in output. Regex=[FAILED]  0.28 sec
Test 'ignore_nested' FAILED: : error during recording:
--------------------------------------------------
/home/opc/rr/build/bin/rr: error while loading shared libraries: libcapnp-0.10.3.so: cannot open shared object file: No such file or directory
--------------------------------------------------
record.out:
--------------------------------------------------
--------------------------------------------------
Test ignore_nested failed, leaving behind /tmp/rr-test-ignore_nested-NziQHtT7g
To replay the failed test, run
  _RR_TRACE_DIR=/tmp/rr-test-ignore_nested-NziQHtT7g rr replay

test 959
    Start 959: ignore_nested-no-syscallbuf

959: Test command: /usr/bin/bash "source_dir/src/test/ignore_nested.run" "ignore_nested" "-n" "bin_dir" "120"
959: Test timeout computed to be: 10000000
959: Test 'ignore_nested' FAILED: : error during recording:
959: --------------------------------------------------
959: /home/opc/rr/build/bin/rr: error while loading shared libraries: libcapnp-0.10.3.so: cannot open shared object file: No such file or directory
959: --------------------------------------------------
959: record.out:
959: --------------------------------------------------
959: --------------------------------------------------
959: Test ignore_nested failed, leaving behind /tmp/rr-test-ignore_nested-dRnibfGur
959: To replay the failed test, run
959:   _RR_TRACE_DIR=/tmp/rr-test-ignore_nested-dRnibfGur rr replay
2/2 Test #959: ignore_nested-no-syscallbuf ......***Failed  Error regular expression found in output. Regex=[FAILED]  0.25 sec
Test 'ignore_nested' FAILED: : error during recording:
--------------------------------------------------
/home/opc/rr/build/bin/rr: error while loading shared libraries: libcapnp-0.10.3.so: cannot open shared object file: No such file or directory
--------------------------------------------------
record.out:
--------------------------------------------------
--------------------------------------------------
Test ignore_nested failed, leaving behind /tmp/rr-test-ignore_nested-dRnibfGur
To replay the failed test, run
  _RR_TRACE_DIR=/tmp/rr-test-ignore_nested-dRnibfGur rr replay


0% tests passed, 2 tests failed out of 2

Total Test time (real) =   0.56 sec

The following tests FAILED:
        958 - ignore_nested (Failed)
        959 - ignore_nested-no-syscallbuf (Failed)

(same when doing export LD_PRELOAD=/usr/local/lib/libcapnp-0.10.3.so, which is definitely recognized in this system)

Reproduce tests 958 and 959 from the reported setup, starting with src/test/ignore_nested.run and the bin/rr executable. Compare these failures with the other tests while capnp is installed under /usr/local/lib and inspect how the test command locates its shared libraries. Done means both ignore_nested variants pass with dependencies in a non-standard directory.