CI: tweak cirrus.yml to prevent OOM and timeout w sanitizer/valgrind

Author: jonasnick

.cirrus.yml

@@ -291,7 +291,7 @@ task:
   container:
     dockerfile: ci/linux-debian.Dockerfile
     cpu: 1
-    memory: 1G
+    memory: 2G
   env:
     ECDH: yes
     RECOVERY: yes
@@ -318,7 +318,7 @@ task:
         UBSAN_OPTIONS: "print_stacktrace=1:halt_on_error=1"
         ASAN_OPTIONS: "strict_string_checks=1:detect_stack_use_after_return=1:detect_leaks=1"
         LSAN_OPTIONS: "use_unaligned=1"
-        TEST_ITERS: 32
+        TEST_ITERS: 16
   # Try to cover many configurations with just a tiny matrix.
   matrix:
     - env: