It's only used for compilation, so don't hang on to it for the entire
lifetime of the routine. Likewise the dylib reference can be local.

Bug: b/177024837
Change-Id: I261e877f983aa3ec52ef61dc6976da75a4fd5efb
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51588Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>