PAL test exception_handling/pal_sxs/test1/paltest_pal_sxs_test1 fails in CI on OSX

[davidwrighton]

Description

The test fails with the following error:

dyld: Library not loaded: @rpath/libpaltest_pal_sxs_test1_dll1.dylib
Referenced from: /tmp/helix/working/AF150A08/w/BFDC0A33/e/exception_handling/pal_sxs/test1/paltest_pal_sxs_test1
Reason: image not found

[davidwrighton]

This is likely a failure specific to CI, as I think the RPATH logic in the CMakeLists.txt isn't translating well to the way we run CI jobs in Helix