native: Improve ${PN}-XXX package name handling

native: Improve ${PN}-XXX package name handling

If a recipe has something like:

RPROVIDES:${PN}-xxx = "yyy"

then the current code will turn this into:

RPROVIDES:${BPN}-native-xxx = "yyy-native"

which can lead to errors. Add in some handling for this special case in the class
extension code.

The corresponding entry in PACKAGES is correctly remapped, the variables aren't
remapped to match though.

Note that merging this does trigger new dependencies to be exposed, some of which
can't be met or are incorrect. These need to be fixed on a case by case basis.

There was also a problem in the existing code when handling anonymous python in
PACKAGES since it would pass bizarre package names like "d)}" to the remapping code.
This patch changes it to ignore anonymous python since in the native case, this likely
isn't wanted anyway. This also then avoids ${PN}-ptest in the native case which was a
common dependency problem.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>