Add test for hashcons warning

Co-authored-by: michael-schwarz <13812333+michael-schwarz@users.noreply.github.com>

Author: Copilot

tests/regression/00-sanity/52-hashcons-warning.c

@@ -0,0 +1,4 @@
+// Test to verify warning is issued when hashconsing is disabled but ARG or Apron is enabled
+int main(void) {
+    return 0;
+}

tests/regression/00-sanity/52-hashcons-warning.t

@@ -0,0 +1,24 @@
+Test that warning is issued when hashconsing is disabled but ARG is enabled:
+
+  $ goblint --disable ana.opt.hashcons --enable exp.arg.enabled 52-hashcons-warning.c 2>&1 | grep -i "hashcons"
+  [Warning] Hashconsing (ana.opt.hashcons) is disabled, but is implicitly enabled because ARG is enabled (exp.arg.enabled)
+
+Test that warning is issued when hashconsing is disabled but Apron is enabled:
+
+  $ goblint --disable ana.opt.hashcons --set ana.activated[+] apron 52-hashcons-warning.c 2>&1 | grep -i "hashcons"
+  [Warning] Hashconsing (ana.opt.hashcons) is disabled, but may be required for Apron domain (ana.activated includes 'apron')
+
+Test that no warning is issued when hashconsing is enabled with ARG:
+
+  $ goblint --enable ana.opt.hashcons --enable exp.arg.enabled 52-hashcons-warning.c 2>&1 | grep -i "hashcons"
+  [1]
+
+Test that no warning is issued when hashconsing is enabled with Apron:
+
+  $ goblint --enable ana.opt.hashcons --set ana.activated[+] apron 52-hashcons-warning.c 2>&1 | grep -i "hashcons"
+  [1]
+
+Test that no warning is issued when hashconsing is disabled without ARG or Apron:
+
+  $ goblint --disable ana.opt.hashcons 52-hashcons-warning.c 2>&1 | grep -i "hashcons"
+  [1]