Don't eagerly remove all catches if try body is empty.

Stemmed from discussion here: http://forum.dlang.org/post/mailman.1094.1371164023.13711.digitalmars-d@puremagic.com

For now, allow the following code in the test suite to be compiled.  Required for gdc to scan for jumps into catch blocks that skip initialisation of exception pointers - also, code generated by dmd currently SEGV's during runtime in test8b and test8c.

All three tests currently fail in gdc with error "cannot goto into catch block", but may fix that at a later date depending on whether or not the code should be considered valid.