[CMake] Fix Python 3 lookup when building LLVM with tests

Remove the find_package(Python3 ...) call from Tooling/CMakeLists.txt as
it would override the python 3 version determined in llvm/CMakeLists.txt.
This call did not respect the LLVM_MINIMUM_PYTHON_VERSION.

This fixes the check-all target when building LLVM on a system where the
default python version is not the minimum required version for running tests.

Reviewed By: serge-sans-paille

Differential Revision: https://reviews.llvm.org/D99715

clang/lib/Tooling/CMakeLists.txt

@@ -13,8 +13,6 @@ add_subdirectory(Syntax)
 add_subdirectory(DependencyScanning)
 add_subdirectory(Transformer)
 
-find_package(Python3 COMPONENTS Interpreter)
-
 # Replace the last lib component of the current binary directory with include
 string(FIND ${CMAKE_CURRENT_BINARY_DIR} "/lib/" PATH_LIB_START REVERSE)
 if(PATH_LIB_START EQUAL -1)