Add SOURCE_DIR and BINARY_DIR directory properties that return the
absolute paths to the corresponding directories. These correspond
to the target properties of the same names that we already have.
Move failure cases from the CMake.{If,List,While,GetProperty} tests over
to the RunCMake.{if,list,while,get_property} tests to use the more
modern infrastructure. This also avoids using REGEX_ESCAPE_STRING to
try to regex-match full paths.