[Profiler] Remove precursory compile-invoke in profiler run to make profiler robust to group2seq

[ayakayorihiro]

This PR makes the profiler's instrumentation approach robust to all intra-component optimization passes. (It's not yet robust to inline - will make an issue about this.)

For a long time, the profiler-specific compiler pipeline relied on having compile-invoke run before profiler-specific passes (uniquefy-enables and profiler-instrumentation). Since we can only instrument within groups (except for continuous assignments), by having compile-invoke run at the very beginning, we were able to instrument when invokes were happening. However, this precursory run of compile-invoke caused cycle discrepancies with group2seq ( #2470 ) and failure in inline (since structural enables of cells cannot be inlined).

As always, any feedback will be very appreciated!

Approach

In order for us to instrument invokes without having to run compile-invoke, we decided to use invoke with comb groups. Specifically, for each invoke, we attach a special comb group in uniquefy-enables, which will be populated with probe wires in profiler-instrumentation. For example, in inline.futil we have:

control { ...
  invoke exp0(base = a_read0_0.out, exp = const3.out)(); 
... }

after running uniquefy-enables, we get:

wires { ...
    comb group invoke_exp00UG { } // new comb group specific to the particular invoke
}
control { ...
  invoke exp0(base = a_read0_0.out, exp = const3.out)() with invoke_exp00UG; 
... }

and then after running profiler-instrumentation we get:

wires { ...
    comb group invoke_exp00UG {
      invoke_exp00UG___main_group_probe.in = 1'd1;
      exp0___invoke_exp00UG___main_cell_probe.in = 1'd1;
    }
}
control { ...
  invoke exp0(base = a_read0_0.out, exp = const3.out)() with invoke_exp00UG; 
... }

Notes

This approach fully assumes that uniquefy-enables will always be followed by profiler-instrumentation (and profiler-instrumentation will always be preceded by uniquefy-enables) since uniquefy-enables adds an empty group. But I think this is ok for now since both passes will only be used under profiling!

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[ayakayorihiro]

I'll take another close look at this PR next week; if it looks alright I will merge!