Rename tests-common into tests-standard

"common" might mean "shared", when we really want to say
"ordinary", "frequent".

Change-Id: If3cdb1693eb24ecb55b6145386bcf6a6a17c6d74
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/tftf/tests/tests.mk b/tftf/tests/tests.mk
index 77b070d..75c409b 100644
--- a/tftf/tests/tests.mk
+++ b/tftf/tests/tests.mk
@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-TESTS ?= common
+TESTS ?= standard
 
 TESTS_FILE	:= tftf/tests/tests-${TESTS}.xml
 TESTS_MAKEFILE	:= tftf/tests/tests-${TESTS}.mk