[SYCL] Fix flaky failure of concurrent cache eviction UT

Author: uditagarwal97

sycl/source/detail/persistent_device_code_cache.cpp

@@ -239,9 +239,19 @@ void PersistentDeviceCodeCache::repopulateCacheSizeFile(
           continue;
       } else {
         // Calculate the size of the cache directory.
-        // During directory size calculation, do not add anything
-        // in the cache. Otherwise, we'll get a std::fs_error.
-        size_t CacheSize = getDirectorySize(CacheRoot);
+        size_t CacheSize = 0;
+
+        // getDirectorySize can throw if any new file is created or removed
+        // in the cache by some other process. Retry in that case.
+        while (true) {
+          try {
+            CacheSize = getDirectorySize(CacheRoot);
+            break;
+          } catch (...) {
+            CacheSize = 0;
+            continue;
+          }
+        }
 
         std::ofstream FileStream{CacheSizeFile};
         FileStream << CacheSize;