Fix #777: don't parse .suffix if <stage> is provided.

Adding a test for this also uncovered an extraneous \r in the runtests script,
fixed now.

Test/baseResults/nosuffix.out

@@ -0,0 +1,15 @@
+nosuffix
+Shader version: 100
+0:? Sequence
+0:1  Function Definition: main( ( global void)
+0:1    Function Parameters: 
+0:3    Sequence
+0:3      move second child to first child ( temp highp 4-component vector of float)
+0:3        'gl_Position' ( gl_Position highp 4-component vector of float Position)
+0:3        Constant:
+0:3          1.000000
+0:3          1.000000
+0:3          1.000000
+0:3          1.000000
+0:?   Linker Objects
+

Test/nosuffix

@@ -0,0 +1,4 @@
+void main()
+{
+    gl_Position = vec4(1.0);
+}

Test/runtests

@@ -66,4 +66,18 @@ else
     echo Tests Failed.
 fi
 
+#
+# Testing -S
+#
+echo Running explicit stage test
+$EXE -i -S vert nosuffix > $TARGETDIR/nosuffix.out
+diff -b $BASEDIR/nosuffix.out $TARGETDIR/nosuffix.out || HASERROR=1
+
+if [ $HASERROR -eq 0 ]
+then
+    echo Tests Succeeded.
+else
+    echo Tests Failed.
+fi
+
 exit $HASERROR