Revert "Feature/issue 2401 alg solver adjoint"

[SteveBronder]

Reverts #2421 it looks like we are having some upstream issues. I thought I sorted out the arena_allocator problem but I think there's another place we need a fix for that. I'll open up a revert revert with a fix tmrw

[stan-buildbot]

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Name	Old Result	New Result	Ratio	Performance change( 1 - new / old )
gp_pois_regr/gp_pois_regr.stan	2.87	2.85	1.01	0.52% faster
low_dim_corr_gauss/low_dim_corr_gauss.stan	0.02	0.02	1.0	-0.34% slower
eight_schools/eight_schools.stan	0.1	0.11	0.94	-5.86% slower
gp_regr/gp_regr.stan	0.15	0.16	0.99	-1.46% slower
irt_2pl/irt_2pl.stan	5.87	5.77	1.02	1.74% faster
performance.compilation	89.2	86.83	1.03	2.66% faster
low_dim_gauss_mix_collapse/low_dim_gauss_mix_collapse.stan	8.52	8.48	1.0	0.44% faster
pkpd/one_comp_mm_elim_abs.stan	29.8	29.4	1.01	1.33% faster
sir/sir.stan	121.83	125.84	0.97	-3.29% slower
gp_regr/gen_gp_data.stan	0.03	0.04	0.98	-1.77% slower
low_dim_gauss_mix/low_dim_gauss_mix.stan	3.05	2.94	1.04	3.69% faster
pkpd/sim_one_comp_mm_elim_abs.stan	0.4	0.39	1.02	1.53% faster
arK/arK.stan	1.83	1.83	1.0	-0.08% slower
arma/arma.stan	0.83	0.92	0.9	-10.67% slower
garch/garch.stan	0.71	0.63	1.12	10.31% faster
Mean result: 1.00116624462

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Jenkins Console Log
Blue Ocean
Commit hash: bfc7987

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Machine information

ProductName: Mac OS X ProductVersion: 10.11.6 BuildVersion: 15G22010

CPU:
Intel(R) Xeon(R) CPU E5-1680 v2 @ 3.00GHz

G++:
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin15.6.0
Thread model: posix

Clang:
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin15.6.0
Thread model: posix

[SteveBronder]

Ty! I'll have a fix for this up tmrw

[rok-cesnovar]

Great! Thanks!