nodes get lost

[kastein]

For some AMRs the splitting algorithm drops nodes completely

• [x] check how often this happens
• [x] adapt splitting algorithm

[kastein]

15 AMRs with lost nodes but in 11 cases "before" or "after" is missing which is expected

Four cases not expected:

• Warning: While splitting blueberry_banana_bread_5_instr1 some amr nodes were lost
• Warning: While splitting cauliflower_mash_3_instr2 some amr nodes were lost
• Warning: While splitting homemade_pizza_dough_3_instr12 some amr nodes were lost
• Warning: While splitting homemade_pizza_dough_4_instr5 some amr nodes were lost

[kastein]

All four original AMRs have issues that need to be fixed at other places or cannot be fixed at all -> if nodes get lost treat graph as non-separable.