GROOVY-10310: STC: retain wildcard flag during diamond generics transfer

3_0_X backport

Author: eric-milles

src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java

@@ -1120,6 +1120,7 @@ private void adjustGenerics(final ClassNode source, final ClassNode target) {
                 GenericsType gt = genericsTypes[i];
                 genericsTypes[i] = new GenericsType(gt.getType(),
                         gt.getUpperBounds(), gt.getLowerBound());
+                genericsTypes[i].setWildcard(gt.isWildcard()); // GROOVY-10310
             }
         }
         target.setGenericsTypes(genericsTypes);