21842 - do not cache absolute file paths

Github issue: magento#21842

In customer and customer_address validation context the validator
factory no longer caches absolute file paths for the validation.xml
files (currently two file) as the file content is evaluated later
in the filesystem directly and the file paths may not be correct
in a multi server setup with shared cache (id_prefix)

lib/internal/Magento/Framework/Validator/Factory.php

@@ -75,17 +75,7 @@ public function __construct(
     protected function _initializeConfigList()
     {
         if (!$this->_configFiles) {
-            $this->_configFiles = $this->cache->load(self::CACHE_KEY);
-            if (!$this->_configFiles) {
-                $this->_configFiles = $this->moduleReader->getConfigurationFiles('validation.xml');
-                $this->cache->save(
-                    $this->getSerializer()->serialize($this->_configFiles->toArray()),
-                    self::CACHE_KEY
-                );
-            } else {
-                $filesArray = $this->getSerializer()->unserialize($this->_configFiles);
-                $this->_configFiles = $this->getFileIteratorFactory()->create(array_keys($filesArray));
-            }
+            $this->_configFiles = $this->moduleReader->getConfigurationFiles('validation.xml');
         }
     }