Copy lnt_graph.js as lnt_regression.js and use it in v4_new_regressions.html and v4_regression_detail.html

This preparation will allow to refactor the graph page to use the library plotly with minimal changes.

OS Laboratory. Huawei Russian Research Institute. Saint-Petersburg

Reviewed By: cmatthews

Differential Revision: https://reviews.llvm.org/D114332

Author: Pavel Kosov