Bug 1650801 - Panic instead of failing gracefully if FreeType failed to initialize. r=gw

Bug 1650662 makes us RELEASE_ASSERT on FreeType initialization earlier
so I think it's unlikely that we ever hit this case in the future.

Differential Revision: https://phabricator.services.mozilla.com/D82390

gfx/wr/webrender/src/platform/unix/font.rs

@@ -336,7 +336,9 @@ impl FontContext {
         } else {
             // TODO(gw): Provide detailed error values.
             Err(ResourceCacheError::new(
-                format!("Failed to initialize FreeType - {}", result)
+                // Once this panic has been here for a while with no issues we should get rid of
+                // ResourceCacheError as this was the only place that could fail previously.
+                panic!("Failed to initialize FreeType - {}", result)
             ))
         }
     }