Fix probability framework allocations (Issue #2036)

[bbbales2]

Fixes #2036

Release notes

Fixes some memory allocation problems with test framework

Checklist

• Math issue Probability test framework doesn't clean up memory properly #2036

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  - 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

[SteveBronder]

Quick Q, could we just make a TearDown() function in the test suite that calls recover_memory() like

  void TearDown() {
    stan::math::recover_memory();
  }

[bbbales2]

I think it makes sense to do the recover memories where they are now. For instance, there are new vars allocated each iteration of the loop here and we recover the memory each time:

math/test/prob/test_fixture_ccdf_log.hpp

Line 412 in 26b33a5

stan::math::recover_memory();

[SteveBronder]

cool cool ping me when this is passing and I'll look it over

[bbbales2]

I'm just gonna put these changes in #2042 since there are problems here.