Run the tests here with: v vlib/v/tests/known_errors/known_errors_test.v

The intended use of this, is for providing samples, that currently do NOT compile, but that a future compiler improvement WILL be able to compile, and to track, whether they were not fixed incidentally, due to an unrelated change/improvement. For example, code that triggers generating invalid C code can go here, and later when a bug is fixed, can be moved to a proper _test.v or .vv/.out pair, outside of the vlib/v/tests/known_errors/testdata/ folder.