Accept string for int64 wrappers (#6491)

diff --git a/php/tests/encode_decode_test.php b/php/tests/encode_decode_test.php
index 5b373bb..f2a5018 100644
--- a/php/tests/encode_decode_test.php
+++ b/php/tests/encode_decode_test.php
@@ -118,12 +118,19 @@
         $this->assertEquals(1, $m->getValue());
     }
 
-    # public function testEncodeTopLevelInt64Value()
-    # {
-    #     $m = new Int64Value();
-    #     $m->setValue(1);
-    #     $this->assertSame("\"1\"", $m->serializeToJsonString());
-    # }
+    public function testDecodeTopLevelInt64ValueAsString()
+    {
+        $m = new Int64Value();
+        $m->mergeFromJsonString("\"1\"");
+        $this->assertEquals(1, $m->getValue());
+    }
+
+    public function testEncodeTopLevelInt64Value()
+    {
+        $m = new Int64Value();
+        $m->setValue(1);
+        $this->assertSame("\"1\"", $m->serializeToJsonString());
+    }
 
     public function testDecodeTopLevelUInt64Value()
     {
@@ -132,12 +139,19 @@
         $this->assertEquals(1, $m->getValue());
     }
 
-    # public function testEncodeTopLevelUInt64Value()
-    # {
-    #     $m = new UInt64Value();
-    #     $m->setValue(1);
-    #     $this->assertSame("\"1\"", $m->serializeToJsonString());
-    # }
+    public function testDecodeTopLevelUInt64ValueAsString()
+    {
+        $m = new UInt64Value();
+        $m->mergeFromJsonString("\"1\"");
+        $this->assertEquals(1, $m->getValue());
+    }
+
+    public function testEncodeTopLevelUInt64Value()
+    {
+        $m = new UInt64Value();
+        $m->setValue(1);
+        $this->assertSame("\"1\"", $m->serializeToJsonString());
+    }
 
     public function testDecodeTopLevelStringValue()
     {