bpo-40455: Fix gcc10+ warning about writing into a section of offset 0 (GH-24384)

diff --git a/Objects/codeobject.c b/Objects/codeobject.c
index f7613e8..69cb31c 100644
--- a/Objects/codeobject.c
+++ b/Objects/codeobject.c
@@ -408,8 +408,8 @@ emit_pair(PyObject **bytes, int *offset, int a, int b)
         if (_PyBytes_Resize(bytes, len * 2) < 0)
             return 0;
     }
-    unsigned char *lnotab = (unsigned char *)
-                    PyBytes_AS_STRING(*bytes) + *offset;
+    unsigned char *lnotab = (unsigned char *) PyBytes_AS_STRING(*bytes);
+    lnotab += *offset;
     *lnotab++ = a;
     *lnotab++ = b;
     *offset += 2;
diff --git a/Python/compile.c b/Python/compile.c
index 8abb5bb..9927f5a 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -5577,9 +5577,8 @@ assemble_emit_linetable_pair(struct assembler *a, int bdelta, int ldelta)
         if (_PyBytes_Resize(&a->a_lnotab, len * 2) < 0)
             return 0;
     }
-    unsigned char *lnotab = (unsigned char *)
-                    PyBytes_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
-
+    unsigned char *lnotab = (unsigned char *) PyBytes_AS_STRING(a->a_lnotab);
+    lnotab += a->a_lnotab_off;
     a->a_lnotab_off += 2;
     *lnotab++ = bdelta;
     *lnotab++ = ldelta;