testsuite: Python3 fix for test_rinpoly.py (fixes https://trac.osgeo.org/grass/ticket/3782) (contributed by pmav99)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74309 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.in.poly/testsuite/test_rinpoly.py

@@ -6,7 +6,7 @@ from grass.script.core import read_command
 
 
 input1 = \
-"""
+b"""
 A
 634308.630394 223320.356473
 640640.712946 223092.401501