Update stack overflow assertion in Source 2

Author: dingyuchen

src/virtual-machines/source-2-with-mark-region-gc.js

@@ -1818,7 +1818,7 @@ function PUSH_OS() {
     B = B + 1;
     HEAP[OS + LAST_CHILD_SLOT] = B; // update address of current top of OS
     HEAP[OS + B] = A;
-    // assert_os_overflow(OS, trace_root);
+    assert_os_overflow(OS, trace_root);
 }
 
 // POP puts the top-most value into RES
@@ -2888,7 +2888,7 @@ function remove_duplicates(lst) {                                             \
         ? null                                                          \
         : accumulate((x, y) => pair(x, remove_all(x, y)), lst, lst);        \
 }                                                                             \
-remove_duplicates(list(1, 2, 3, 4, 2, 1, 2, 5)); ");
+remove_duplicates(list(1, 2, 2, 1)); ");
 
 // parse_and_compile_and_run(20, 20, 4, "                                                       \
 // function permutations(lst) {                                                  \

src/virtual-machines/source-2.js

@@ -1255,7 +1255,9 @@ function PUSH_OS() {
     B = B + 1;
     HEAP[OS + LAST_CHILD_SLOT] = B; // update address of current top of OS
     HEAP[OS + B] = A;
-    if (B >= HEAP[OS + LAST_CHILD_SLOT]) {
+    if (B >= HEAP[OS + SIZE_SLOT]) {
+        show_node(OS);
+        display(B, "new top");
         error('stack overflow');
     } else {}
 }
@@ -1941,6 +1943,17 @@ function run() {
     }
 }
 
+function show_node(address) {
+  const tag = HEAP[address];
+  const size = HEAP[address + SIZE_SLOT];
+  display("======================");
+  display(node_kind(tag), address);
+  for (let i = 1; i < size + 1; i = i + 1) {
+    display(stringify(address + i) + ": " + stringify(HEAP[address + i]));
+  }
+  display("======================");
+}
+
 parse_and_compile_and_run("                                                       \
 function subset(lst) {                                           \
     return is_null(lst)                             \