Merge new tests into existing files where appropriate

- bulkwritecommand-ctor-ordered-002: add getWriteConcernErrors() assertion
  (verifies empty array when only write errors occur); removes the need
  for a separate bulkwritecommandexception-getwriteconcernerrors-001.phpt
- session-getTransactionOptions-001: add combined-options case (all four
  transaction options together); removes the need for a separate
  session-startTransaction-002.phpt

Author: GromNaN

tests/bulkwritecommand/bulkwritecommand-ctor-ordered-002.phpt

@@ -23,6 +23,7 @@ try {
     printf("%s(%d): %s\n", get_class($e), $e->getCode(), $e->getMessage());
     var_dump($e->getPartialResult());
     var_dump($e->getWriteErrors());
+    var_dump($e->getWriteConcernErrors());
 }
 
 ?>
@@ -64,4 +65,6 @@ array(1) {
     }
   }
 }
+array(0) {
+}
 ===DONE===

tests/exception/bulkwritecommandexception-getwriteconcernerrors-001.phpt

@@ -19,6 +19,12 @@ $options = [
     ['readConcern' => new \MongoDB\Driver\ReadConcern('majority')],
     ['readPreference' => new \MongoDB\Driver\ReadPreference('primaryPreferred')],
     ['writeConcern' => new \MongoDB\Driver\WriteConcern('majority')],
+    [
+        'maxCommitTimeMS' => 5000,
+        'readConcern' => new \MongoDB\Driver\ReadConcern(\MongoDB\Driver\ReadConcern::MAJORITY),
+        'readPreference' => new \MongoDB\Driver\ReadPreference(\MongoDB\Driver\ReadPreference::PRIMARY),
+        'writeConcern' => new \MongoDB\Driver\WriteConcern(\MongoDB\Driver\WriteConcern::MAJORITY),
+    ],
 ];
 
 foreach ($options as $test) {
@@ -82,4 +88,23 @@ array(2) {
     string(8) "majority"
   }
 }
+array(4) {
+  ["maxCommitTimeMS"]=>
+  int(5000)
+  ["readConcern"]=>
+  object(MongoDB\Driver\ReadConcern)#%d (1) {
+    ["level"]=>
+    string(8) "majority"
+  }
+  ["readPreference"]=>
+  object(MongoDB\Driver\ReadPreference)#%d (1) {
+    ["mode"]=>
+    string(7) "primary"
+  }
+  ["writeConcern"]=>
+  object(MongoDB\Driver\WriteConcern)#%d (1) {
+    ["w"]=>
+    string(8) "majority"
+  }
+}
 ===DONE===