Revert "Ship globalThis 🎉"

This reverts commit 4dac9872.

Reason for revert: Speculative revert for layout test failures:
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8-Blink%20Linux%2064/25970

E.g.:
virtual/service-worker-servicification/http/tests/serviceworker/webexposed/global-interface-listing-service-worker.html

Original change's description:
> Ship globalThis 🎉
> 
> Proposal repository:
> https://github.com/tc39/proposal-global
> 
> Intent to ship:
> https://groups.google.com/d/msg/v8-users/Vkoh0wXRwaM/Yt7MpzhkAgAJ
> 
> Bug: v8:5537
> Change-Id: I60a6c5375165d89548db12fef454a64137d04c27
> Reviewed-on: https://chromium-review.googlesource.com/1195494
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
> Commit-Queue: Mathias Bynens <mathias@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#55543}

TBR=adamk@chromium.org,gsathya@chromium.org,mathias@chromium.org

Change-Id: Iacb484d36ba2c8002336038660450b240006e0ab
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:5537
Reviewed-on: https://chromium-review.googlesource.com/1199743Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55564}

src/flag-definitions.h

@@ -230,7 +230,8 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
   V(harmony_public_fields, "harmony public fields in class literals")      \
   V(harmony_private_fields, "harmony private fields in class literals")    \
   V(harmony_numeric_separator, "harmony numeric separator between digits") \
-  V(harmony_string_matchall, "harmony String.prototype.matchAll")
+  V(harmony_string_matchall, "harmony String.prototype.matchAll")          \
+  V(harmony_global, "harmony global")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                              \
@@ -242,8 +243,7 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
   V(harmony_dynamic_import, "harmony dynamic import")                    \
   V(harmony_array_prototype_values, "harmony Array.prototype.values")    \
   V(harmony_array_flat, "harmony Array.prototype.{flat,flatMap}")        \
-  V(harmony_symbol_description, "harmony Symbol.prototype.description")  \
-  V(harmony_global, "harmony globalThis")
+  V(harmony_symbol_description, "harmony Symbol.prototype.description")
 
 // Once a shipping feature has proved stable in the wild, it will be dropped
 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,

test/mjsunit/harmony/global.js

@@ -13,7 +13,7 @@ assertEquals(globalThis.globalThis.globalThis.globalThis, this);
 {
   const realm = Realm.create();
   assertEquals(Realm.global(realm), Realm.eval(realm, 'globalThis'));
-  assertNotEquals(Realm.global(realm), globalThis);
+  assertTrue(Realm.global(realm) !== globalThis);
 }
 
 {