perf(pg): avoid useless spread (brianc#3379)

* perf(pg): avoid useless spread

* fix: missing initialization

Author: cesco69

packages/pg/lib/result.js

@@ -88,19 +88,18 @@ class Result {
       this._parsers = new Array(fieldDescriptions.length)
     }
 
-    var row = {}
+    this._prebuiltEmptyResultObject = {}
 
     for (var i = 0; i < fieldDescriptions.length; i++) {
       var desc = fieldDescriptions[i]
-      row[desc.name] = null
+      this._prebuiltEmptyResultObject[desc.name] = null
 
       if (this._types) {
         this._parsers[i] = this._types.getTypeParser(desc.dataTypeID, desc.format || 'text')
       } else {
         this._parsers[i] = types.getTypeParser(desc.dataTypeID, desc.format || 'text')
       }
     }
-    this._prebuiltEmptyResultObject = { ...row }
   }
 }