Add a build with MBEDTLS_ERROR_STRERROR_DUMMY

Add a build with MBEDTLS_ERROR_STRERROR_DUMMY but not MBEDTLS_ERROR_C.
Previously, both options were enabled by default, but
MBEDTLS_ERROR_STRERROR_DUMMY only matters when MBEDTLS_ERROR_C is
enabled, so its effect was not tested.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 757a9ec..88a3eaf 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -1895,6 +1895,20 @@
     make test
 }
 
+component_test_no_strings () {
+    msg "build: no strings" # ~10s
+    scripts/config.py full
+    # Disable options that activate a large amount of string constants.
+    scripts/config.py unset MBEDTLS_DEBUG_C
+    scripts/config.py unset MBEDTLS_ERROR_C
+    scripts/config.py set MBEDTLS_ERROR_STRERROR_DUMMY
+    scripts/config.py unset MBEDTLS_VERSION_FEATURES
+    make CFLAGS='-Werror -Os'
+
+    msg "test: no strings" # ~ 10s
+    make test
+}
+
 component_build_arm_none_eabi_gcc () {
     msg "build: ${ARM_NONE_EABI_GCC_PREFIX}gcc -O1" # ~ 10s
     scripts/config.py baremetal