Added an example to demonstrate precondition violation for expressions like 1+n during type inference.

git-svn-id: https://svn.eiffel.com/eiffelstudio/trunk@95212 8089f293-4706-0410-a29e-feb5c42a2edf
Avoided reporting VOMB(2) violation when type of an inspect expression is unknown (test#inference013).

git-svn-id: https://svn.eiffel.com/eiffelstudio/trunk@95213 8089f293-4706-0410-a29e-feb5c42a2edf
Changed status of test#inference013 that now passes.

git-svn-id: https://svn.eiffel.com/eiffelstudio/trunk@95214 8089f293-4706-0410-a29e-feb5c42a2edf
Changed precondition of `is_frozen_type_compatible' to be able to accept unknown target type (test#inference014).

git-svn-id: https://svn.eiffel.com/eiffelstudio/trunk@95215 8089f293-4706-0410-a29e-feb5c42a2edf