Moved verify changes Jenkins step to shared libraries.

[serban-nicusor-toptal]

Summary

This PR removes code that was moved into the Shared Libraries while also fixing a bug reported in #1773

Tests

...

Side Effects

No

Checklist

• Math issue #(issue number)

• Copyright holder: (fill in copyright holder information)

  The copyright holder is typically you or your assignee, such as a university or company. By submitting this pull request, the copyright holder is agreeing to the license the submitted work under the following licenses:
  - Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
  - Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

• the basic tests are passing

  • unit tests pass (to run, use: ./runTests.py test/unit)
  • header checks pass, (make test-headers)
  • dependencies checks pass, (make test-math-dependencies)
  • docs build, (make doxygen)
  • code passes the built in C++ standards checks (make cpplint)

• the code is written in idiomatic C++ and changes are documented in the doxygen

• the new changes are tested

[rok-cesnovar]

Thanks! Looks good.

[stan-buildbot]

---

Name	Old Result	New Result	Ratio	Performance change( 1 - new / old )
gp_pois_regr/gp_pois_regr.stan	4.84	4.86	0.99	-0.5% slower
low_dim_corr_gauss/low_dim_corr_gauss.stan	0.02	0.02	1.02	1.54% faster
eight_schools/eight_schools.stan	0.09	0.09	0.95	-4.81% slower
gp_regr/gp_regr.stan	0.22	0.22	1.0	-0.35% slower
irt_2pl/irt_2pl.stan	6.45	6.43	1.0	0.32% faster
performance.compilation	87.75	86.44	1.02	1.5% faster
low_dim_gauss_mix_collapse/low_dim_gauss_mix_collapse.stan	7.53	7.52	1.0	0.06% faster
pkpd/one_comp_mm_elim_abs.stan	22.54	21.02	1.07	6.75% faster
sir/sir.stan	94.55	94.61	1.0	-0.06% slower
gp_regr/gen_gp_data.stan	0.05	0.05	0.97	-3.28% slower
low_dim_gauss_mix/low_dim_gauss_mix.stan	2.95	2.95	1.0	-0.04% slower
pkpd/sim_one_comp_mm_elim_abs.stan	0.31	0.33	0.92	-8.14% slower
arK/arK.stan	1.74	1.76	0.99	-1.1% slower
arma/arma.stan	0.65	0.66	0.99	-0.54% slower
garch/garch.stan	0.51	0.51	1.0	0.34% faster
Mean result: 0.99543946949

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Jenkins Console Log
Blue Ocean
Commit hash: 496db6b

---

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