[debuginfo-test][cross-project-test] New cross-project lit directory/debuginfo-test suite has moved

Hi all,

TL;DR: there’s a new top-level project called cross-project-test for tests which require multiple LLVM projects, which replaces debuginfo-test. You may need to update LLVM_ENABLE_PROJECT accordingly.

Just one slight correction to my previous email, caused by a faulty memory! In the “Actions you may need to take:” block, point 3 refers to “check-debuginfo-tests” when it should be simply “check-debuginfo”.