[lldb] Match test dependencies name to other LLVM projects.

Other LLVM projects use the suffix `-depends` for the test dependencies,
however LLDB uses `-deps` and seems to be the only project under the
LLVM to do so.

In order to make the projects more homogeneous, switch all the
references to `lldb-test-deps` to `lldb-test-depends`.

Additionally, provide a compatibility target with the old name and
depending on the new name, in order to not break anyone workflow.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D102889