Build: Update tf-m-tests default commit

Update Version of Test Repo

Signed-off-by: Jianliang Shen <jianliang.shen@arm.com>
Change-Id: I8a1f1e5d86596d82f3abb8ffd1b797b76acf0389
diff --git a/config/config_default.cmake b/config/config_default.cmake
index 4c661dd..60fc1f6 100644
--- a/config/config_default.cmake
+++ b/config/config_default.cmake
@@ -179,7 +179,7 @@
 set(TFM_MBEDCRYPTO_PLATFORM_EXTRA_CONFIG_PATH "" CACHE PATH "Config to append to standard Mbed Crypto config, used by platforms to cnfigure feature support")
 
 set(TFM_TEST_REPO_PATH                  "DOWNLOAD"  CACHE PATH      "Path to TFM-TEST repo (or DOWNLOAD to fetch automatically")
-set(TFM_TEST_REPO_VERSION               "e0dd80a"   CACHE STRING    "The version of tf-m-tests to use")
+set(TFM_TEST_REPO_VERSION               "2a20b57"   CACHE STRING    "The version of tf-m-tests to use")
 set(CMSIS_5_PATH                        "DOWNLOAD"  CACHE PATH      "Path to CMSIS_5 (or DOWNLOAD to fetch automatically")
 
 set(MCUBOOT_PATH                        "DOWNLOAD"        CACHE PATH      "Path to MCUboot (or DOWNLOAD to fetch automatically")