Merge #1545: cmake: Do not set CTEST_TEST_TARGET_ALIAS

f87a358 cmake: Do not set `CTEST_TEST_TARGET_ALIAS` (Hennadii Stepanov)

Pull request description:

  An alias for the "test" target can be confusing for the downstream project.

  For instance, when integrating using `add_subdirectory(secp256k1 EXCLUDE_FROM_ALL)` (see hebasto/bitcoin#192), test binaries are not being built by default. But the `check` alias target is exposed to the downstream project build system, which in turn fails:
  ```
  $ make -C build check
  ...
  Unable to find executable: /home/hebasto/git/bitcoin/build/src/secp256k1/src/exhaustive_tests
  3/3 Test #3: exhaustive_tests .................***Not Run   0.00 sec

  0% tests passed, 3 tests failed out of 3

  Total Test time (real) =   0.03 sec

  The following tests FAILED:
    1 - noverify_tests (Not Run)
    2 - tests (Not Run)
    3 - exhaustive_tests (Not Run)
  Errors while running CTest
  ...
  ```

  This PR fixes this issue by deleting the `CTEST_TEST_TARGET_ALIAS` usage.

ACKs for top commit:
  real-or-random:
    utACK f87a358

Tree-SHA512: ccf3f30939cf1747471ea15260f7caa6dad3f510e5771245ecbfbef3cc0b0e7c8ac551519d0892bf2544c91467d8d67d2c6e6bc52f56c384b174b88bcf377d4a

CMakeLists.txt

@@ -273,10 +273,6 @@ if(SECP256K1_BUILD_CTIME_TESTS)
   unset(msan_enabled)
 endif()
 
-# Ask CTest to create a "check" target (e.g., make check) as alias for the "test" target.
-# CTEST_TEST_TARGET_ALIAS is not documented but supposed to be user-facing.
-# See: https://gitlab.kitware.com/cmake/cmake/-/commit/816c9d1aa1f2b42d40c81a991b68c96eb12b6d2
-set(CTEST_TEST_TARGET_ALIAS check)
 include(CTest)
 # We do not use CTest's BUILD_TESTING because a single toggle for all tests is too coarse for our needs.
 mark_as_advanced(BUILD_TESTING)