test: add lib path env when node_shared=true

When building the node with `--shared` option, the major output is the
shared library. However, we still build a node executable which links
to the shared lib. It's for testing purpose. When testing with the
executable, some test cases move/copy the executable, change the
relative path to the shared library and fail. Using lib path env would
solve the issue. However, in macOS, need to change the install name for
the shared library and use rpath in the executable. In AIX, `-brtl`
linker option rebinds the symbols in the executable and addon modules
could use them.

Signed-off-by: Yihong Wang <yh.wang@ibm.com>

PR-URL: https://github.com/nodejs/node/pull/18626
Refs: https://github.com/nodejs/node/issues/18535


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>