Remove BFGS line search support functions from anonymous namespace since we're unit testing them seperately.
Remove BFGS line search support functions from anonymous namespace since we're unit testing them seperately.

stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/stan,stan-dev/math