Tests/InstallParallel: unset `NINJA_STATUS`

The install tests check that the output matches content including the
"status" portion of the output. Unset the variable to avoid leakage from
development environments.

Tests/RunCMake/InstallParallel/RunCMakeTest.cmake

@@ -25,7 +25,7 @@ function(install_test test)
       set(INSTALL_COUNT 1)
     endif()
     set(RunCMake-check-file check-num-installs.cmake)
-    run_cmake_command(${test}-install ${CMAKE_COMMAND} --build . --config Debug ${ARGS_ARGS})
+    run_cmake_command(${test}-install ${CMAKE_COMMAND} -E env --unset=NINJA_STATUS ${CMAKE_COMMAND} --build . --config Debug ${ARGS_ARGS})
     unset(RunCMake-check-file)
   else()
     if (ARGS_COMPONENT)
@@ -42,7 +42,7 @@ function(install_test test)
     endif()
     set(INSTALL_MANIFEST ${RunCMake_TEST_BINARY_DIR}/${INSTALL_MANIFEST})
     set(RunCMake-check-file check-manifest.cmake)
-    run_cmake_command(${test}-install ${CMAKE_COMMAND} --install . ${ARGS_ARGS})
+    run_cmake_command(${test}-install ${CMAKE_COMMAND} -E env --unset=NINJA_STATUS ${CMAKE_COMMAND} --install . ${ARGS_ARGS})
     unset(RunCMake-check-file)
   endif()
 endfunction()