Remove accidental addition of MBEDTLS_TEST_HOOKS

Remove MBEDTLS_TEST_HOOKS from the default config, to which it was
erroneously added.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 62d9d4b..a8bc45e 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2243,7 +2243,7 @@
  *
  * Uncomment to enable invasive tests.
  */
-#define MBEDTLS_TEST_HOOKS
+//#define MBEDTLS_TEST_HOOKS
 
 /**
  * \def MBEDTLS_THREADING_ALT