inference: check lower bounds assignability to upper bounds

lub may break some capture invariants

GitOrigin-RevId: c7857bf255c357471fd9f14fc161d2ca03769f4b

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting8/LowerBoundAssignabilityCheck.java

@@ -0,0 +1,11 @@
+class MyTest<T> {
+  static void m(Ref<? super String> commentRef) {
+    commentRef = coalesce(commentRef, commentRef);
+  }
+
+  static <T> T coalesce(T t1, T t2) {
+    return t1;
+  }
+
+  static class Ref<T> { }
+}