The ornamental design for compressor, as shown and described.
FIG. 1 is a left side view of a compressor showing our new design;
FIG. 2 is a right side view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a right side perspective view thereof; and,
FIG. 8 is a left side perspective view thereof.
The broken line showing of the trademark “GEA” is included for the purpose of illustrating environmental matter and forms no part of the claimed design.