Missing test cases for executive services API parameter/return combinations

[jphickey]

Is your feature request related to a problem? Please describe.
The following parameter/return code combinations are not exercised by the executive services functional test:

  + condition: CFE_ES_CreateChildTask[any]=>CFE_ES_ERR_CHILD_TASK_CREATE
  + condition: CFE_ES_CreateChildTask[any]=>CFE_ES_ERR_RESOURCEID_NOT_VALID
  + condition: CFE_ES_DeleteChildTask[any]=>CFE_ES_ERR_CHILD_TASK_DELETE
  + condition: CFE_ES_DeleteChildTask[any]=>CFE_ES_ERR_CHILD_TASK_DELETE_MAIN_TASK
  + condition: CFE_ES_GetAppID[any]=>CFE_ES_ERR_RESOURCEID_NOT_VALID
  + condition: CFE_ES_GetAppIDByName[<null-pointer>@1]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetAppInfo[<null-pointer>@0]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetAppInfo[any]=>CFE_ES_BAD_ARGUMENT
  + condition: CFE_ES_GetLibIDByName[<null-pointer>@1]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetLibName[<null-pointer>@0]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetLibName[<zero-value>@2]=>ERROR_ZERO_VALUE
  + condition: CFE_ES_GetMemPoolStats[<null-pointer>@0]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetMemPoolStats[CFE_ES_MemHandle_t@1]=>ERROR_RESOURCEID_INVALID
  + condition: CFE_ES_GetMemPoolStats[any]=>CFE_ES_BAD_ARGUMENT
  + condition: CFE_ES_GetPoolBufInfo[any]=>CFE_ES_BUFFER_NOT_IN_POOL
  + condition: CFE_ES_GetTaskID[any]=>CFE_ES_ERR_RESOURCEID_NOT_VALID
  + condition: CFE_ES_GetTaskIDByName[<null-pointer>@1]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetTaskInfo[<null-pointer>@0]=>ERROR_NULL_POINTER
  + condition: CFE_ES_GetTaskInfo[any]=>CFE_ES_BAD_ARGUMENT
  + condition: CFE_ES_PoolCreateEx[any]=>CFE_ES_NO_RESOURCE_IDS_AVAILABLE
  + condition: CFE_ES_PoolCreateEx[any]=>CFE_STATUS_EXTERNAL_RESOURCE_FAIL
  + condition: CFE_ES_RegisterCDS[any]=>CFE_ES_CDS_INVALID
  + condition: CFE_ES_RestoreFromCDS[any]=>CFE_ES_CDS_BLOCK_CRC_ERR
  + condition: CFE_ES_WaitForSystemState[any]=>CFE_ES_OPERATION_TIMED_OUT
  + condition: CFE_ES_WriteToSysLog[<null-pointer>@0]=>ERROR_NULL_POINTER
  + condition: CFE_ES_WriteToSysLog[any]=>CFE_ES_BAD_ARGUMENT
  + condition: CFE_ES_WriteToSysLog[any]=>CFE_SUCCESS

Describe the solution you'd like
Solve each missing case in one of three ways:

1. Add a test case covering that option
2. Update the API documentation
3. Add a @covtest tag if the combination can only be reasonably achieved in a coverage environment

Additional context
Part of/related to #1724 (each subsystem will be handled separately)

Requester Info
Joseph Hickey, Vantage Systems, Inc.