Trac #33213: remove SAGE_TMP from tmp_dir() and tmp_filename().

These two functions will now use whatever python decides is the
appropriate place for temporary files on the system.

src/sage/misc/temporary_file.py

@@ -96,8 +96,7 @@ def tmp_dir(name="dir_", ext=""):
         0
         sage: f.close()
     """
-    from sage.misc.misc import SAGE_TMP
-    tmp = tempfile.mkdtemp(prefix=name, suffix=ext, dir=str(SAGE_TMP))
+    tmp = tempfile.mkdtemp(prefix=name, suffix=ext)
     name = os.path.abspath(tmp)
     return name + os.sep
 
@@ -146,8 +145,7 @@ def tmp_filename(name="tmp_", ext=""):
         0
         sage: f.close()
     """
-    from sage.misc.misc import SAGE_TMP
-    handle, tmp = tempfile.mkstemp(prefix=name, suffix=ext, dir=str(SAGE_TMP))
+    handle, tmp = tempfile.mkstemp(prefix=name, suffix=ext)
     os.close(handle)
     name = os.path.abspath(tmp)
     return name