Fixes error to extract constructor name using build --prod

[leandrogehlen]

Short description of what this resolves:

Fixes error to extract constructor name using build --prod

Fixes:
When we needs extract constructor name from class, (like migrations), usinb build --prod the
uglify process can't do it.

Example

classm201707121646_create_post{up(): Array<string>{return[`ALTER TABLE "post" ALTER COLUMN "title" RENAME TO "name"`,`ALTER TABLE "post" ADD COLUMN "category_id" INTEGER`];}}constMIGRATIONS: Array<any>=[m201707121646_criar_pessoa];MIGRATIONS.forEach((migration)=>{constinstance=newmigration();console.log((<any>instance).constructor.name);}