build: improve circleci config (#33881)

* build: fix conditional restore of git cache

* build: split lint out of setup.yml

.circleci/config/build.js

@@ -0,0 +1,34 @@
+const cp = require('child_process');
+const fs = require('fs-extra');
+const path = require('path');
+const yaml = require('js-yaml');
+
+const STAGING_DIR = path.resolve(__dirname, '..', 'config-staging');
+
+function copyAndExpand(dir = './') {
+    const absDir = path.resolve(__dirname, dir);
+    const targetDir = path.resolve(STAGING_DIR, dir);
+
+    if (!fs.existsSync(targetDir)) {
+        fs.mkdirSync(targetDir);
+    }
+
+    for (const file of fs.readdirSync(absDir)) {
+        if (!file.endsWith('.yml')) {
+            if (fs.statSync(path.resolve(absDir, file)).isDirectory()) {
+                copyAndExpand(path.join(dir, file));
+            }
+            continue;
+        }
+
+        fs.writeFileSync(path.resolve(targetDir, file), yaml.dump(yaml.load(fs.readFileSync(path.resolve(absDir, file), 'utf8')), {
+            noRefs: true,
+        }));
+    }
+}
+
+if (fs.pathExists(STAGING_DIR)) fs.removeSync(STAGING_DIR);
+copyAndExpand();
+
+const output = cp.spawnSync(process.env.CIRCLECI_BINARY || 'circleci', ['config', 'pack', STAGING_DIR]);
+fs.writeFileSync(path.resolve(STAGING_DIR, 'built.yml'), output.stdout.toString());