no debug symbols for internal-only method types.

now 15% overhead instead of 30% in binaries.

R=ken
OCL=33235
CL=33288

src/cmd/6g/gsubr.c

@@ -940,6 +940,7 @@ naddr(Node *n, Addr *a)
 			a->etype = simtype[n->type->etype];
 			a->width = n->type->width;
 			if(n->sym != S && strncmp(n->sym->name, "autotmp_", 8) != 0)
+			if(n->type->etype != TFUNC || n->type->thistuple == 0)
 				a->gotype = typename(n->type)->left->sym;
 		}
 		a->offset = n->xoffset;

src/cmd/8g/gsubr.c

@@ -1692,6 +1692,7 @@ naddr(Node *n, Addr *a)
 		if(n->type != T) {
 			a->etype = simtype[n->type->etype];
 			if(n->sym != S && strncmp(n->sym->name, "autotmp_", 8) != 0)
+			if(n->type->etype != TFUNC || n->type->thistuple == 0)
 				a->gotype = typename(n->type)->left->sym;
 		}
 		a->offset = n->xoffset;