Previously, when defining a package for a class, LaunchedURLClassLoader
would use the manifest from the first location that contained the
required package. If the package was split across multiple locations,
this could lead to the manifest from a jar other than the one that
contains the class being used.
This commit updates LaunchedURLClassLoader so that it will use the
manifest of the jar file that contains the class which triggered the
definition of the package.
Closes gh-5485
c0b74119e0