bug symfony#39555 [FrameworkBundle] Fix NFS detection on macOs (jderusse)

This PR was merged into the 5.2 branch.

Discussion
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[FrameworkBundle] Fix NFS detection on macOs

| Q             | A
| ------------- | ---
| Branch?       | 5.2
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix symfony#39552
| License       | MIT
| Doc PR        | -

Commits
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79718fb Fix NFS detection on macOs

Author: derrabus

src/Symfony/Bundle/FrameworkBundle/Command/CacheClearCommand.php

@@ -207,8 +207,8 @@ private function isNfs(string $dir): bool
 
         if (null === $mounts) {
             $mounts = [];
-            if ('/' === \DIRECTORY_SEPARATOR && $mounts = @file('/proc/mounts')) {
-                foreach ($mounts as $mount) {
+            if ('/' === \DIRECTORY_SEPARATOR && $files = @file('/proc/mounts')) {
+                foreach ($files as $mount) {
                     $mount = \array_slice(explode(' ', $mount), 1, -3);
                     if (!\in_array(array_pop($mount), ['vboxsf', 'nfs'])) {
                         continue;