Fix NullPointerExceprion when getGID() was called on null (#688)

Author: LonelyMidoriya

src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java

@@ -126,6 +126,9 @@ public float getWidth(int code) {
                 width = getWidth(TrueTypePredefined.NOTDEF_STRING);
             }
             if (width == -1) {
+                if (this.parser.getCmapParser() == null) {
+                    return 0;
+                }
                 int gid = this.parser.getCmapParser().getGID(code);
                 return getWidthWithCheck(gid);
             }
@@ -221,6 +224,9 @@ private float getWidthSymbolic(int code) {
             gid = cmap10.getGlyph(code);
             return getWidthWithCheck(gid);
         }
+        if (this.parser.getCmapParser() == null) {
+            return 0;
+        }
         gid = this.parser.getCmapParser().getGID(code);
         return getWidthWithCheck(gid);
     }