Fix dependencies on targets linked through object libraries

When an object library is used via target_link_libraries, any targets listed in the object library's INTERFACE_LINK_LIBRARIES closure should become direct dependencies of the consuming target. However, these were accidentally left out by cmComputeTargetDepends::CollectTargetDepends because object libraries are encountered through external object sources first and then added to the emitted set which blocks them from being processed as link dependencies.

This was not noticed by the test case in !2725 (merged) because the relevant dependency appears transitively through the object library target itself.

Re-order the logic to process link dependencies first, and then external object sources. That way object libraries used via target_link_libraries will be treated as such by dependency analysis.

This also adds missing backtrace information for object libraries used via target_link_libraries. The missing information was mentioned in a FIXME comment in the RunCMake.FileAPI test added by !2706 (merged). That comment itself was dropped by !4333 (merged), but we can now update the corresponding location in the .json files to have the now-expected backtrace information.

Fixes: #20421 (closed)