[kernel] add non-regression test for const local inits

tests/syntax/local-init-const.i

+/*run.config
+  OPT: -no-autoload-plugins -load-module eva,scope -eva -eva-verbose 0
+ */
+unsigned id(unsigned x) { return x; }
+
+void main() {
+  unsigned const r = id(1 > 2 ? 1 : 2);
+  //@ assert written_r: r == 2;
+}

tests/syntax/oracle/local-init-const.res.oracle

+[kernel] Parsing tests/syntax/local-init-const.i (no preprocessing)