Greylist libraries are attempted to be loaded in the default ns

Some of the greylist libraries can be in directories other than
/system/lib. For example, libnativehelper.so is moved from the directory
to /apex/com.android.runtime/lib.

Previous behavior for greylist libraries is to find the lib under
/system/lib while "within" the current namespace which is usually the
classloader-namespace. Since the libs no longer exist there, linker
fails to load it and no further attempt is made.

This change fixes the problem by loading the greylist libs "from" the
default namespace. Since there is a link from the default namespace to
the namespace where the moved libraries are intended to be loaded (e.g.,
the 'runtime' namespace for libnativehelper.so), the call is successful.

Bug: 124201397
Test: bionic-unit-tests

Change-Id: I11d15993d18896bdf663c408f9e40d8a607c9b80