fixup-dyn-deps: handle duplicate dynamic library paths
fixup-dyn-deps: handle duplicate dynamic library paths

Summary:
On GitHub Actions macos-10.15 image, some of the build dependencies
for Watchman reference
/usr/local/opt/openssl@1.1/lib/libcrypto.1.1.dylib and others
reference
/usr/local/Cellar/openssl@1.1/1.1.1m/lib/libcrypto.1.1.dylib.

To avoid overwriting libcrypto in the artifact directory, key
processed_deps on the destination path.

Reviewed By: xavierd

Differential Revision: D34882663

fbshipit-source-id: 60d021bf9956d9b3e34e8945ccec234d31031369

nodakai/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman