Add failing test for multiline constant declaration (rsim#207)

Reproduces the issue where accessing a package constant fails when
the assignment is wrapped to the next line, as Oracle 19c does in
sys.dbms_db_version.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yahonda

spec/plsql/variable_spec.rb

@@ -340,6 +340,32 @@
 
   end
 
+  describe "constants with multiline declaration" do
+    before(:all) do
+      plsql.connect! CONNECTION_PARAMS
+      plsql.execute "DROP PACKAGE test_multiline_pkg" rescue nil
+      plsql.execute <<-SQL
+        CREATE OR REPLACE PACKAGE test_multiline_pkg IS
+          multiline_constant CONSTANT PLS_INTEGER :=
+            42;
+        END;
+      SQL
+      plsql.execute <<-SQL
+        CREATE OR REPLACE PACKAGE BODY test_multiline_pkg IS
+        END;
+      SQL
+    end
+
+    after(:all) do
+      plsql.execute "DROP PACKAGE test_multiline_pkg" rescue nil
+      plsql.logoff
+    end
+
+    it "should get constant with multiline assignment" do
+      expect(plsql.test_multiline_pkg.multiline_constant).to eq(42)
+    end
+  end
+
   describe "object type" do
     before(:all) do
       plsql.connect! CONNECTION_PARAMS