PY-83588 support pydevd-pycharm installation on Linux & <=3.10 Python

with PEP 517 support (introduced in PY-81877)
building wheels is done in isolation,
that means - there is no `setup_cython.py`
available for import, one suggested workaround
(used in `debugpy` as well) is to prepend
the project root to `sys.path` - ugly but works


(cherry picked from commit 67e6d93f0d19e20b16685255714c46a7563a037f)

IJ-MR-173624

GitOrigin-RevId: 13457b1c9c447b296b6378d4ad1933d371b5c9d8

python/helpers/pydev/setup.py

@@ -29,6 +29,11 @@ from distutils.extension import Extension
 from setuptools import setup
 from setuptools.dist import Distribution
 
+# PEP 517 compatibility
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from setup_cython import get_frame_eval_extension_name
+del sys.path[0]
+
 
 class BinaryDistribution(Distribution):
     def is_pure(self):
@@ -192,7 +197,6 @@ if sys.platform not in ('darwin', 'win32'):
         ]
     ))
     if (3, 6) <= sys.version_info <= (3, 10):
-        from setup_cython import get_frame_eval_extension_name
         frame_eval_extension_name = get_frame_eval_extension_name()
         args_with_binaries["ext_modules"].append(
             # In this setup, don't even try to compile with cython, just go with the .c file which should've