VS_DEBUGGER_WORKING_DIRECTORY is not honoured by the generator

### Brief Issue Summary

The debugger and run-without-debugger (run in terminal) do not honour the working directory set for individual targets.

### Expected:

Both debugger and run-without-debugger run my target from the specified (by VS_DEBUGGER_WORKING_DIRECTORY) working directory.

### Apparent Behavior:

Debugger and Run-In-Terminal both attempt to run my target binaries from the root directory of the project as the working directory.

### Platform and Versions

- **Operating System**: Ubuntu 18.04
- **CMake Version**: 3.15.3
- **VSCode Version**: 1.33.0
- **CMake Tools Extension Version**: 1.1.3
- **Compiler/Toolchain**: GCC 7.3.0

Start by tracing how VS_DEBUGGER_WORKING_DIRECTORY is consumed for individual targets in the debugger and run-without-debugger paths. Reproduce the issue on the stated Ubuntu, CMake, VS Code, and CMake Tools versions; done means both launch modes use the target-specific working directory instead of the project root.

Written by the indexing model from the issue text.