Revert "Maintain 1.8 compatibility in Dir.chdir spec"

This reverts commit e124632ac52f92d7dccd44e8c906673fc6993ab9.
Revert "Propagate Ruby's cwd to Java via Dir.chdir"

This reverts commit 42198651fe5ead7d14df97641588a9dbf4711e9e.

Need to fix Embedded tests.