CMake: Mark benchmark executables with a property

This will be used in a follow up patch to identify them.

Task-number: QTBUG-93625
Task-number: QTBUG-112212
Change-Id: I39d5eb9f79ac67af0808efeda4d7f4e0a6908cc9
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
(cherry picked from commit df040fb1115071fbea80213814b7dc34b17ba085)
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

cmake/QtExecutableHelpers.cmake

@@ -35,6 +35,7 @@ function(qt_internal_add_executable name)
     set_target_properties(${name} PROPERTIES
         _qt_is_test_executable ${arg_QT_TEST}
         _qt_is_manual_test ${arg_QT_MANUAL_TEST}
+        _qt_is_benchmark_test ${arg_QT_BENCHMARK_TEST}
     )
 
     if(ANDROID)

cmake/QtTargetHelpers.cmake

@@ -452,6 +452,7 @@ macro(qt_internal_setup_default_target_function_options)
         QT_APP
         QT_TEST
         QT_MANUAL_TEST
+        QT_BENCHMARK_TEST
         NO_UNITY_BUILD
         ${__qt_internal_sbom_optional_args}
     )

cmake/QtTestHelpers.cmake

@@ -41,6 +41,7 @@ function(qt_internal_add_benchmark target)
     qt_internal_add_executable(${target}
         NO_INSTALL # we don't install benchmarks
         NO_UNITY_BUILD # excluded by default
+        QT_BENCHMARK_TEST
         OUTPUT_DIRECTORY "${arg_OUTPUT_DIRECTORY}" # avoid polluting bin directory
         ${exec_args}
     )