Disable asan errors on null allocation in all.sh

Such error was raised in platform tests,
and it's a valid test case.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>

tests/scripts/all.sh

@@ -188,6 +188,9 @@ pre_initialize_variables () {
     # default to -O2, use -Ox _after_ this if you want another level
     ASAN_CFLAGS='-O2 -Werror -fsanitize=address,undefined -fno-sanitize-recover=all'
 
+    # Platform tests have an allocation that returns null
+    export ASAN_OPTIONS="allocator_may_return_null=1"
+
     # Gather the list of available components. These are the functions
     # defined in this script whose name starts with "component_".
     # Parse the script with sed. This way we get the functions in the order