Compiled Exception table isn't created when using a shared mu library
Currently the compiled exception table is constructed in
vm_resume, however this is not run for shared librarys? (at least isn't in the test_rpython:throw_catch test).
We need to create this table (or update it) whenever we load in new libraries generated by the compiler (but it must be done after the loading and relocation, so that the calls to dlysym get the correct address of callsite and catch labels).