Merge pull request swiftlang#32496 from compnerd/you-shall-not-pass

build: remove workaround for python fallback

Author: compnerd

CMakeLists.txt

@@ -899,13 +899,7 @@ if(NOT CMAKE_SYSTEM_NAME STREQUAL "Darwin")
 endif()
 
 find_package(Python2 COMPONENTS Interpreter REQUIRED)
-find_package(Python3 COMPONENTS Interpreter)
-if(NOT Python3_Interpreter_FOUND)
-  message(WARNING "Python3 not found, using python2 as a fallback")
-  add_executable(Python3::Interpreter IMPORTED)
-  set_target_properties(Python3::Interpreter PROPERTIES
-    IMPORTED_LOCATION ${Python2_EXECUTABLE})
-endif()
+find_package(Python3 COMPONENTS Interpreter REQUIRED)
 
 #
 # Find optional dependencies.