Add end to end test devoted to ctest

[hippo91]

This changes test system

The following changes are proposed:

This PR is a proposal to add end to end test devoted to ctest part of the extension.

It adds a directory named single-root-ctest in the end-to-end-tests directory.

It also changes slightly the source directory in order:

• to avoid early return in the refreshTests method (ctest.ts file) when in testing mode;
• to change the return code of the ctest method (cmakeProject.ts) so that successfull test return 0 and failure returns -1.

The purpose of this change

When doing change to the ctest part of the extension, i did not feel very comfortable not being backed up by tests.
This PR tries to circumvent this.