Revert "Merge pull request #1212 from stan-dev/feature/faster-ad-tls-v5"

This reverts commit 5e76d67f, reversing
changes made to ec52b8be.

Feature/issue 1217 change name of copy function

Fixes #1175. bugfix/gp_matern52_cov-fails

Fixes #1213. Feature/issue 1213 Trimming boost

Issue 1218 beta function and gradients

Faster TLS v5

Merge branch 'feature/faster-ad-tls-v5' of https://github.com/stan-dev/math into feature/faster-ad-tls-v5

Feature/issue 1071 ode time varying

Feature/issue 1062 ode speedup

Fixes #1220. Feature/issue 1220 Real FFT half spectrum

Merge branch 'feature/issue-1062-ode-speedup' of https://github.com/stan-dev/math into feature/issue-1062-ode-speedup

# Conflicts:
#	stan/math/prim/mat/fun/cholesky_decompose.hpp
#	test/unit/math/opencl/add_test.cpp
#	test/unit/math/opencl/cholesky_decompose_test.cpp
#	test/unit/math/opencl/copy_test.cpp
#	test/unit/math/opencl/kernel_cl_test.cpp

Merge branch 'feature/faster-ad-tls-v5' of https://github.com/stan-dev/math into feature/faster-ad-tls-v5

This reverts commit 0bf46b01.

Revert "make explicit use of pointer to AD tape for faster access without relying on compiler optimizations"

This reverts commit 236b6d96.