[enhancement] Add ability to discern asserts from different instances of the same proc

[koblonczek]

What's hard to do? (limit 100 words)

In a tree of procs, when one the child procs throws an assertion, there's no way to know which instance of the child proc did it. This hampers debuggability when there are multiple instances of the same proc. Only reference to the file and line are printed. For example, in a system with multiple RAMs this doesn't give enough info which RAM had its assertion violated:

xls/examples/ram.x:254:14-254:106
0252:       let mem_initialized_as_bits =
0253:         std::convert_to_bits_msb0(array_rev(mem_initialized[read_req.addr]));
0254:       assert!(read_req.mask & !mem_initialized_as_bits == uN[NUM_PARTITIONS]:0, "memory_not_initialized")
~~~~~~~~~~~~~~~~~~~^------------------------------------------------------------------------------------------^ FailureError: The program being interpreted failed! memory_not_initialized
0255:     } else { () };

Current best alternative workaround (limit 100 words)

To differentiate between different instances one can add an instantiation parameter that will serve as an "ID" of the proc (while supplying unique values during instantiation) and add additional logging statements:

proc SomeProc<ID: u32, ...> {
  next(state: State) {
    // assertions
    if (!condition) {
      trace_fmt!("{:x} assertion_message", ID);
    } else {};
    assert!(condition, "assertion_message");    
  }
}

Your view of the "best case XLS enhancement" (limit 100 words)

Having additional info printed about where in the hierarchy the error came from.
Related to #1236, although that one asks for printing hierarchy in trace! and trace_fmt! calls.