Revert D32283178: Add linalg.solve_triangular
Test Plan: revert-hammer
Differential Revision:
D32283178 (https://github.com/pytorch/pytorch/commit/0706607abc4ff48179f551a2afb2ce15ec63932f)
Original commit changeset: deb672e6e52f
fbshipit-source-id: d2a3421292147426cc61c2f063b721acf9004755
