CMakeParseArguments: Remove superfluous includes of CMakeParseArguments

Because cmake_parse_arguments() has been implemented as a native
command, there is no need to include(CMakeParseArguments) anymore.
Its inclusion has been removed from several CMake modules.

Tests/CMakeOnly/CMakeLists.txt has been changed to include the
*building* CMake's copy of CMakeParseArguments rather than the
*built* CMake's copy. This file included the *built* copy because
when this file was introduced, CMake could still be built with versions
that didn't supply cmake_parse_arguments(). Now, CMake requires 3.1 or
greater, where cmake_parse_arguments() existed but was still in the
form of a module, so we include it from the *building* CMake.

Modules/CheckIPOSupported.cmake

@@ -51,8 +51,6 @@ Examples
 
 #]=======================================================================]
 
-include(CMakeParseArguments) # cmake_parse_arguments
-
 # X_RESULT - name of the final result variable
 # X_OUTPUT - name of the variable with information about error
 macro(_ipo_not_supported output)

Modules/FeatureSummary.cmake

@@ -97,8 +97,6 @@ Functions
 
 #]=======================================================================]
 
-include(CMakeParseArguments)
-
 function(_FS_GET_FEATURE_SUMMARY _property _var _includeQuiet)
 
   get_property(_fsPkgTypes GLOBAL PROPERTY FeatureSummary_PKG_TYPES)

Modules/FindProtobuf.cmake

@@ -121,8 +121,6 @@ Example:
 #]=======================================================================]
 
 function(protobuf_generate)
-  include(CMakeParseArguments)
-
   set(_options APPEND_PATH DESCRIPTORS)
   set(_singleargs LANGUAGE OUT_VAR EXPORT_MACRO PROTOC_OUT_DIR)
   if(COMMAND target_sources)

Tests/CMakeOnly/CMakeLists.txt

@@ -56,7 +56,7 @@ add_test(CMakeOnly.ProjectInclude ${CMAKE_CMAKE_COMMAND}
   -P ${CMAKE_CURRENT_BINARY_DIR}/Test.cmake
   )
 
-include(${CMAKE_SOURCE_DIR}/Modules/CMakeParseArguments.cmake)
+include(CMakeParseArguments)
 
 function(add_major_test module)
   cmake_parse_arguments(MAJOR_TEST "NOLANG" "VERSION_VAR" "VERSIONS" ${ARGN})