Updated upb to pick up several bugfixes (#7740)

* Updated upb to pick up several bugfixes. This fixes most conformance failures.

* Updated golden file, now that we are serializing as packed by default.

* Set "packed" properly: it is on by default for packable fields in proto3.

* Updated failure list for PHP now that we properly respect "packed".

* Temporarily disable encode_decode_test

Co-authored-by: Joshua Haberman <jhaberman@gmail.com>
diff --git a/php/tests/php_implementation_test.php b/php/tests/php_implementation_test.php
index db3c361..f9fc1fd 100644
--- a/php/tests/php_implementation_test.php
+++ b/php/tests/php_implementation_test.php
@@ -515,7 +515,7 @@
     {
         $m = new TestMessage();
         TestUtil::setTestMessage($m);
-        $this->assertSame(518, $m->byteSize());
+        $this->assertSame(504, $m->byteSize());
     }
 
     public function testPackedByteSize()