Fix socket problem when running with Emscripten CPython build (#1077)

* SO_REUSEADDR is not supported in EMSCRIPTEN

* Review feedback, make handling SO_REUSEADDR behave like other options

* Remove accidental import

* Fix formatting

src/debugpy/common/sockets.py

@@ -41,7 +41,10 @@ def _new_sock():
     if sys.platform == "win32":
         sock.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
     else:
-        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        try:
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        except (AttributeError, OSError):
+            pass  # Not available everywhere
 
     # Set TCP keepalive on an open socket.
     # It activates after 1 second (TCP_KEEPIDLE,) of idleness,