Use -O2 for build+test with earliest compilers

The compilation is slower but we get more potential warnings and running the
tests is faster.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 229e6df..fcc20f4 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -3031,7 +3031,7 @@
 
 component_test_clang_earliest_opt () {
     scripts/config.py full
-    test_build_opt 'full config' "$CLANG_EARLIEST" -O0
+    test_build_opt 'full config' "$CLANG_EARLIEST" -O2
 }
 support_test_clang_earliest_opt () {
     type "$CLANG_EARLIEST" >/dev/null 2>/dev/null
@@ -3047,7 +3047,7 @@
 
 component_test_gcc_earliest_opt () {
     scripts/config.py full
-    test_build_opt 'full config' "$GCC_EARLIEST" -O0
+    test_build_opt 'full config' "$GCC_EARLIEST" -O2
 }
 support_test_gcc_earliest_opt () {
     type "$GCC_EARLIEST" >/dev/null 2>/dev/null