This is unnecessary and inconsistent with "builtin" case in which the
docstrings are not indented in the generated C++ code, thus making it
impossible to write tests working in both cases.
Most of the changes in this commit simply remove the extra whitespace from the
expected values in the tests.
Update Doxygen-specific Python unit tests to work with the new indentation.
Update one of Doxygen-specific Java tests to still build with the new handling
of srcdir.