[LinkerWrapper] report on missing libraries

The linker wrapper does its own library searching for static archives
that can contain device code. The device linking phases happen before
the host linking phases so that we can generate the necessary
registration code and link it in with the rest of the code. Previously,
If a library containing needed device code was not found the execution
would continue silently until it failed with undefined symbols. This
patch allows the linker wrapper to perform its own check beforehand to
catch these errors.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D137180