Use shebang-defined shell for verify-bundle-size (#8644)

In-line with changes made in 81f22d6.

Author: alxndrsn

bin/verify-build.sh

@@ -6,4 +6,4 @@
 npm run build
 
 node ./bin/verify-dependencies.js
-sh ./bin/verify-bundle-size.sh
+./bin/verify-bundle-size.sh