Work around another javac bug in InvalidLink

PiperOrigin-RevId: 391833917

Author: amalloy

core/src/main/java/com/google/errorprone/bugpatterns/javadoc/InvalidLink.java

@@ -156,7 +156,7 @@ public Void visitLink(LinkTree linkTree, Void unused) {
  element =
  JavacTrees.instance(state.context)
  .getElement(new DocTreePath(getCurrentPath(), linkTree.getReference()));
- } catch (NullPointerException e) {
+ } catch (NullPointerException | AssertionError e) {
  // TODO(b/176098078): remove once JDK 12 is the minimum supported version
  // https://bugs.openjdk.java.net/browse/JDK-8200432
  } finally {