The ornamental design for a toilettank flush handle, as shown and described.
FIG. 1 is a perspective view of a toilet tank flush handle showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a rear elevation view thereof.
The broken line shown in FIG. 7 of the drawings are included for the purpose of illustrating a portion of the toilet tank flush handle that forms no part of the claimed design.