[WIP] PIM-1983 : improve perfs of ProductBuilder

Bug fix: [yes|no]
Feature addition: [yes|no]
Backwards compatibility break: [yes|no]
Unit test passes: [yes|no]
Specs passes: [yes|no]
Replaced unit test classes removed: [yes|no]
Behat scenario passes: [yes|no]
Checkstyle issues: [yes|no]*
ChangeLog updated: [yes|no]
Documentation PR: [link to the documentation PR if there is one]
Fixes the following jira: