GenericBackendV2 should fail when the backend cannot allocate the basis gate because its size (backport #12653)

[mergify[bot]]

Summary

GenericBackendV2 should not accept backends that are too small for certain gates. The following examples should be rejected:

GenericBackendV2(num_qubits=1, basis_gates=["cx", "id"])

GenericBackendV2(num_qubits=2, basis_gates=["ccx", "id"])

@ElePT found this!

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This is an automatic backport of pull request #12653 done by Mergify.

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[coveralls]

Pull Request Test Coverage Report for Build 9676645295

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 12 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.02%) to 89.935%

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Files with Coverage Reduction	New Missed Lines	%
qiskit/transpiler/passes/synthesis/unitary_synthesis.py	2	88.2%
crates/qasm2/src/lex.rs	4	92.62%
crates/qasm2/src/parse.rs	6	97.61%
<!--	Total:	12		-->

Totals
Change from base Build 9663344566:	0.02%
Covered Lines:	61831
Relevant Lines:	68751

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💛 - Coveralls