Inserting with query builder attempts to insert a default row when values is empty array

[lazarljubenovic]

Issue type:

[ ] question
[x] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[x] postgres
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[x] latest
[ ] @next
[ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:

        await this.tableRepo
          .createQueryBuilder()
          .insert()
          .into(Table)
          .values([])
          .execute()

INSERT INTO "table"("row1", "row2", "row3") VALUES (DEFAULT, DEFAULT, DEFAULT)

[nicofrand]

Same thing using getRepository(Entity).insert([])

[minism]

Bumping. This seems like a pretty easy edge case to solve.