Revert "[CMake][libcxx] Move Python check to main CMake file"

This reverts commit 39441fe9f0.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291728 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/Modules/HandleOutOfTreeLLVM.cmake

@@ -95,6 +95,13 @@ macro(configure_out_of_tree_llvm)
   endif()
 
   # LLVM Options --------------------------------------------------------------
+  include(FindPythonInterp)
+  if( NOT PYTHONINTERP_FOUND )
+    message(WARNING "Failed to find python interpreter. "
+                    "The libc++ test suite will be disabled.")
+    set(LLVM_INCLUDE_TESTS OFF)
+  endif()
+
   if (NOT DEFINED LLVM_INCLUDE_TESTS)
     set(LLVM_INCLUDE_TESTS ${LLVM_FOUND})
   endif()