validation: Add general purpose test suite

Add a general purpose test suite for validation tests.

This is the first test suite generated from a specification item in the
rtems-central repository.

Update #3959.

cpukit/doxygen/top-level-groups.h

@@ -42,3 +42,9 @@
  *
  * @brief RTEMS Implementation.
  */
+
+/**
+ * @defgroup RTEMSTestSuites Test Suites
+ *
+ * @brief Collection of Test Suites
+ */