vstest crashed when running some particular tests

When I let run all tests (ca. 800 tests) in my solution, after some time a popup window with error is shown that vstest.executionengine.x86.exe has stopped working.

Some Examples of problem details, that I get are here:

Problem signature:
  Problem Event Name:   CLR20r3
  Problem Signature 01: vstest.executionengine.x86.exe
  Problem Signature 02: 14.0.23107.0
  Problem Signature 03: 559b7b6c
  Problem Signature 04: mscorlib
  Problem Signature 05: 4.6.1076.0
  Problem Signature 06: 56d79fa2
  Problem Signature 07: 0
  Problem Signature 08: ffffffff
  Problem Signature 09: System.StackOverflowException
  OS Version:   6.1.7601.2.1.0.256.48
  Locale ID:    1051
  Additional Information 1: 5cd2
  Additional Information 2: 5cd2742c12da7dd4b1d5bf900186a452
  Additional Information 3: 2fe2
  Additional Information 4: 2fe276cacf1c00cd7a2aed7b27f5a5f9

Problem signature:
  Problem Event Name:   APPCRASH
  Application Name: vstest.executionengine.x86.exe
  Application Version:  14.0.23107.0
  Application Timestamp:    559b7b6c
  Fault Module Name:    clr.dll
  Fault Module Version: 4.6.1076.0
  Fault Module Timestamp:   56d7a0ff
  Exception Code:   c00000fd
  Exception Offset: 00003567
  OS Version:   6.1.7601.2.1.0.256.48
  Locale ID:    1051
  Additional Information 1: 0127
  Additional Information 2: 01273c850b3b6fc6378d3f666887788e
  Additional Information 3: 0786
  Additional Information 4: 07866ddaac895bff9a7fa791fcdaa4a7

In VS output window I get:

------ Run test started ------
The active Test Run was aborted because the execution process exited unexpectedly. To investigate further, enable local crash dumps either at the machine level or for process vstest.executionengine.x86.exe. Go to more details: http://ift.tt/1gd34OP
========== Run test finished: 0 run (0:03:55,0267906) ==========

When I tried to enable local crash dumps I found out that there is no such registry key so I haven't been able to do it.

I Located all test (22 tests) causing crash of vstest.---.exe, commented them and run all test again and without those "wrong" tests. Everything runs fine.

What can be wrong with those tests? They all are old tests which was working in past. How to locate a problem?