cmake: set CMP0037 policy to NEW

To fix deprecation warning, CMP0037 policy was changed to NEW for cmake
3.11 and above.

CMP0037 old behavior (cmake 2.8.12) allowed target names such as test.
In cmake 3.10 and below names test, help and etc. were reserved.

Starting from cmake 3.11 these names are only reserved when the
corresponding feature is enabled (e.g. by including the CTest or CPack
modules). Tarantool does not use CTest so the name test can be used.

Closes #3587