SharedLibraryInfo.isNative() returns true for native libs

This CL fixes a bug that SharedLibraryInfo.isNative() returns false
even for native shared libraries. This was because when a
SharedLibraryInfo is copied to a new SharedLibraryInfo (to add some
extra info about declaring package, etc.), the native-ness was
mistakenly ignored. Fixing the issue.

Also, the old constructor of SharedLibraryInfo that doesn't accept the
native-ness was removed to prevent similar mistakes.

Bug: 142191088
Test: atest CtsUsesNativeLibraryTest
Test: write an app that calls PackageManager.getSharedLibraries()
and inspect the mIsNative fields in the returned list. Entries for
native shared libs all have mIsNative=false. Will add a testcase to
the CTS test when isNative() becomes an API.

Change-Id: I35d9530f332614e0444448feec70a4461c9bbfa8