test: update menu modifier chord tests to workaround chromium bug

It seems that after the recent chromium update, two menu e2e tests started
to fail consistently given the use of `Key.chord` with a modifier key. The
problem seems to be that chromium has a bug with the revision we are using,
where the chord `Key.NULL` reset key is sent as actual character to the active
element instead of the key state/modifier state being reset.

Related: https://bugs.chromium.org/p/chromedriver/issues/detail?id=3999.

It's low-effort to just release the keys manually here.

(cherry picked from commit e99d633)

src/material-experimental/mdc-menu/menu.e2e.spec.ts

@@ -1,4 +1,4 @@
-import {browser, by, element, ExpectedConditions, Key, protractor} from 'protractor';
+import {browser, by, element, ExpectedConditions, Key} from 'protractor';
 import {
   expectAlignedWith,
   expectFocusOn,
@@ -135,7 +135,8 @@ describe('MDC-based menu', () => {
       await pressKeys(Key.TAB, Key.ENTER);
       await expectToExist(menuSelector);
 
-      await pressKeys(protractor.Key.chord(Key.SHIFT, Key.TAB));
+      // Press SHIFT+TAB, but make sure to release SHIFT again.
+      await pressKeys(Key.SHIFT, Key.TAB, Key.SHIFT);
       await expectToExist(menuSelector, false);
     });
 
@@ -149,13 +150,14 @@ describe('MDC-based menu', () => {
     });
 
     it('should focus before and after trigger when tabbing past items', async () => {
-      let shiftTab = protractor.Key.chord(Key.SHIFT, Key.TAB);
+      // Press SHIFT+TAB, but make sure to release SHIFT again.
+      let shiftTab = [Key.SHIFT, Key.TAB, Key.SHIFT];
 
       await pressKeys(Key.ENTER, Key.TAB);
       await expectFocusOn(page.triggerTwo());
 
       // navigate back to trigger
-      await pressKeys(shiftTab, Key.ENTER, shiftTab);
+      await pressKeys(...shiftTab, Key.ENTER, ...shiftTab);
       await expectFocusOn(page.start());
     });
   });

src/material/menu/menu.e2e.spec.ts

@@ -1,4 +1,4 @@
-import {browser, by, element, ExpectedConditions, Key, protractor} from 'protractor';
+import {browser, by, element, ExpectedConditions, Key} from 'protractor';
 import {
   expectAlignedWith,
   expectFocusOn,
@@ -135,7 +135,8 @@ describe('menu', () => {
       await pressKeys(Key.TAB, Key.ENTER);
       await expectToExist(menuSelector);
 
-      await pressKeys(protractor.Key.chord(Key.SHIFT, Key.TAB));
+      // Press SHIFT+TAB, but make sure to release SHIFT again.
+      await pressKeys(Key.SHIFT, Key.TAB, Key.SHIFT);
       await expectToExist(menuSelector, false);
     });
 
@@ -149,13 +150,14 @@ describe('menu', () => {
     });
 
     it('should focus before and after trigger when tabbing past items', async () => {
-      let shiftTab = protractor.Key.chord(Key.SHIFT, Key.TAB);
+      // Press SHIFT+TAB, but make sure to release SHIFT again.
+      let shiftTab = [Key.SHIFT, Key.TAB, Key.SHIFT];
 
       await pressKeys(Key.ENTER, Key.TAB);
       await expectFocusOn(page.triggerTwo());
 
       // navigate back to trigger
-      await pressKeys(shiftTab, Key.ENTER, shiftTab);
+      await pressKeys(...shiftTab, Key.ENTER, ...shiftTab);
       await expectFocusOn(page.start());
     });
   });