The new verifyUSRToDeclReconstruction checking cannot handle @abi when the abi name does not exist in real ast

[ktoso]

Description

When doing this PR #84944 we noticed the complete_diagnostics_concurrency.swift test will fail in the verifyUSRToDeclReconstruction since it cannot handle @abi properly

@hamishknight has ideas how to fix it, but for now we have disabled this checking for @abi attribute

Reproduction

See: https://github.com/swiftlang/swift/pull/84944/commits

@abi(func doesNotExist()) func example() {}

should be sufficient, but that PR's first commit reproduces entirely

Expected behavior

should not crash

Environment

current main, 6.3 development

Additional information

No response

[ktoso]

There's one additional workaround in f2eb567