Fix bug in circuit.insert.

[codrut3]

Change _group_into_moment_compatible to take into account measurement and control keys. Otherwise two incompatible operations can be put in the same moment.
I also changed _can_add_op_at to look at measurement and control keys.
I added unit tests that show the issue.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.57%. Comparing base (ceb9432) to head (b11b2de).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7823      +/-   ##
==========================================
- Coverage   99.57%   99.57%   -0.01%     
==========================================
  Files        1102     1102              
  Lines       98772    98828      +56     
==========================================
+ Hits        98352    98407      +55     
- Misses        420      421       +1     

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[daxfohl]

Allowing multiple measurements to the same key in the same moment was a requirement from the HW team. Unless that has changed, this would be breaking.

[codrut3]

Thank you for pointing this out @daxfohl ! Doesn't this mean this condition here is also wrong:

Cirq/cirq-core/cirq/circuits/circuit.py

Line 2146 in ceb9432

not op_measurement_keys.isdisjoint(moment_measurement_keys)

[daxfohl]

Maybe. Though it can't be removed completely, because then it could fall through to earlier moments and break commutativity. (There's a lot of https://xkcd.com/1172/ in the circuit construction code).