tests: fix r_move_itable_realloc to run on Linux

tests: fix r_move_itable_realloc to run on Linux

The check for the various unsupported OSes incorrectly checked if
the string "FreeBSD" was true, which it always was.  Fix this.

Update the expect file as commit v1.46.4-17-g4ea80d031c7e did to
adjust the total number of blocks requested during resize.

Change-Id: I272dbec67ab30bac6413eb4cba0e3ab00183b893
Fixes: 5a3ea3905f ("tests: force test file systems to be built for Linux OS")
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>