megatest should confirm that directories in tests-paths are directories before looking for tests.

To duplicate, make MT_RUN_AREA_HOME a file instead of link.

Sample stack dump:

Error: (directory) cannot open directory - Not a directory:

        Call history:

        tests.scm:57: glob
        tests.scm:51: g435
        tests.scm:52: string-split
        tests.scm:52: last
        tests.scm:53: conc
        tests.scm:54: hash-table-ref/default
        tests.scm:55: file-exists?
        tests.scm:56: hash-table-set!
        tests.scm:60: loop
        tests.scm:50: file-exists?
        tests.scm:60: loop
        tests.scm:50: file-exists?
        tests.scm:60: loop
        tests.scm:50: file-exists?
        tests.scm:57: conc
        tests.scm:57: glob              <--