Revert setting optimization flag(use O2)

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index f2a37f2..4b22040 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -187,7 +187,7 @@
 
     # CFLAGS and LDFLAGS for Asan builds that don't use CMake
     # default to -O2, use -Ox _after_ this if you want another level
-    ASAN_CFLAGS='-O0 -Werror -fsanitize=address,undefined -fno-sanitize-recover=all'
+    ASAN_CFLAGS='-O2 -Werror -fsanitize=address,undefined -fno-sanitize-recover=all'
 
     # Gather the list of available components. These are the functions
     # defined in this script whose name starts with "component_".