test: add regression tests for vm bugs

Add the regression test script presented in
nodejs#10806 to `test/parallel` and
re-add the original regression test for
nodejs#10223 in `test/known_issues`.

test/known_issues/test-vm-global-non-writable-properties.js

@@ -0,0 +1,16 @@
+'use strict';
+// https://github.com/nodejs/node/issues/10223
+
+require('../common');
+const assert = require('assert');
+const vm = require('vm');
+
+const ctx = vm.createContext();
+vm.runInContext('Object.defineProperty(this, "x", { value: 42 })', ctx);
+assert.strictEqual(ctx.x, undefined);  // Not copied out by cloneProperty().
+assert.strictEqual(vm.runInContext('x', ctx), 42);
+vm.runInContext('x = 0', ctx);                      // Does not throw but x...
+assert.strictEqual(vm.runInContext('x', ctx), 42);  // ...should be unaltered.
+assert.throws(() => vm.runInContext('"use strict"; x = 0', ctx),
+              /Cannot assign to read only property 'x'/);
+assert.strictEqual(vm.runInContext('x', ctx), 42);

test/parallel/test-vm-global-assignment.js

@@ -0,0 +1,15 @@
+'use strict';
+// Regression test for https://github.com/nodejs/node/issues/10806
+
+require('../common');
+const assert = require('assert');
+const vm = require('vm');
+const ctx = vm.createContext({ open() { } });
+const window = vm.runInContext('this', ctx);
+const other = 123;
+
+assert.notStrictEqual(window.open, other);
+window.open = other;
+assert.strictEqual(window.open, other);
+window.open = other;
+assert.strictEqual(window.open, other);