fix brace misplaced error

Signed-off-by: Howard Zhang <howard.zhang@arm.com>

test/syscalls/linux/32bit.cc

@@ -240,9 +240,9 @@ TEST(Call32Bit, Disallowed) {
   }
 }
 
-}  // namespace
-
 #endif
 
+}  // namespace
+
 }  // namespace testing
 }  // namespace gvisor