The ornamental design for a portablehand-held test instrument, as shown and described.
FIG. 1 is a perspective view of the ornamental design;
FIG. 2 is a front elevational view of the ornamental design;
FIG. 3 is a rear elevational view of the ornamental design;
FIG. 4 is a right side elevational view of the ornamental design;
FIG. 5 is a left side elevation view of the ornamental design;
FIG. 6 is a is a top plan view of the ornamental design; and,
FIG. 7 is a bottom plan view of the ornamental design.
The broken line showing of structural features is included for the purpose of illustrating non-claimed subject matter and forms no part of the claimed design.