GLContext: Don't map compatibility profiles to core profile if the latter are not available (restrict profile aliasing) ; GLProfile does this - Simplification.

GLContext shall not map compatibility profiles to core profile if the latter is are not available (restrict profile aliasing).

If a user requests a straight GL3 core profile, don't answer with a compatibility profile, e.g. GL4bc.

Hence this patch exposes the true GL profile situation more honestly the the user!

User can already query profile mappings via GLProfile, i.e.
  - GL2GL3,
  - GL4ES3, or via
  - getMaximum
  - getMaxFixedFunc
  - getMaxProgrammable
  - getMaxProgrammableCore

This also fixes an issue when a user requests 'getMaxProgrammableCore'
but would receive a GL4bc profile.
Bug 1038 - Allow skipping detection of certain GLProfiles: Skip 'ARB_create_context' context creation extension via property 'jogl.disable.openglarbcontext'; ...

Only allow the exclusions if platform OS is not OSX:
  - jogl.disable.openglcore
  - jogl.disable.openglarbcontext

Since on OSX they are known to work reliable and there is not other method
if receiving a higher GL profile than core and ARB.

This also removes the restrictions on X11 and Windows,
where profiles >= GL3 must be created using ARB_create_context.
Hence this is allowed now.