Remove 'm' SOABI flag that no longer exists in 3.9+

See https://docs.python.org/3/library/sys.html#sys.abiflags

> Changed in version 3.8: Default flags became an empty string (m flag for pymalloc has been removed).

Author: abravalheri

setuptools/command/bdist_wheel.py

@@ -111,19 +111,11 @@ def get_abi_tag() -> str | None:
     impl = tags.interpreter_name()
     if not soabi and impl in ("cp", "pp") and hasattr(sys, "maxunicode"):
         d = ""
-        m = ""
         u = ""
         if get_flag("Py_DEBUG", hasattr(sys, "gettotalrefcount"), warn=(impl == "cp")):
             d = "d"
 
-        if get_flag(
-            "WITH_PYMALLOC",
-            impl == "cp",
-            warn=(impl == "cp" and sys.version_info < (3, 8)),
-        ) and sys.version_info < (3, 8):
-            m = "m"
-
-        abi = f"{impl}{tags.interpreter_version()}{d}{m}{u}"
+        abi = f"{impl}{tags.interpreter_version()}{d}{u}"
     elif soabi and impl == "cp" and soabi.startswith("cpython"):
         # non-Windows
         abi = "cp" + soabi.split("-")[1]