Better Gnarly error message (#8270)

If this ever happens it would be good to have some information.

src/main/java/org/broadinstitute/hellbender/tools/walkers/gnarlyGenotyper/GnarlyGenotyperEngine.java

@@ -257,7 +257,7 @@ else if (variant.hasAttribute(GATKVCFConstants.AS_RAW_QUAL_APPROX_KEY)) {
                 }
             }
             catch (final Exception e) {
-                throw new IllegalStateException("Something went wrong: ", e);
+                throw new IllegalStateException("Unable to instantiate InfoFieldAnnotation: ", e);
             }
         }
         //since AS_FS and AS_SOR share the same raw key, we have to wait to remove raw keys until all the finalized values are added
@@ -527,4 +527,4 @@ private static int[] getSBFieldAsIntArray(Genotype g) {
           }
       }
     }
-}
+}