glcpp/tests: update testname in help string

Rather than hardcoding glcpp/other use `basename "$0"` which expands
appropriatelly.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

src/compiler/glsl/glcpp/tests/glcpp-test-cr-lf.sh

@@ -51,7 +51,7 @@ run_test ()
 usage ()
 {
 	cat <<EOF
-Usage: glcpp-cr-lf [options...]
+Usage: `basename "$0"` [options...]
 
 Run the entire glcpp-test suite several times, each time with each source
 file transformed to use a non-standard line-termination character. Each

src/compiler/glsl/glcpp/tests/glcpp-test.sh

@@ -22,7 +22,7 @@ trap 'rm $test.valgrind-errors; exit 1' INT QUIT
 usage ()
 {
     cat <<EOF
-Usage: glcpp [options...]
+Usage: `basename "$0"` [options...]
 
 Run the test suite for mesa's GLSL pre-processor.