Remove bogus assertion for script contexts.

We assume that during bootstrapping, we won't create script contexts.
This is wrong, since JavaScript code in extensions may introduce
let/const variables.

R=jgruber@chromium.org

Change-Id: I02595abdbb65f41faffc90bde142849bbde6b554
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1666994
Auto-Submit: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63161}

src/runtime/runtime-scopes.cc

@@ -678,9 +678,6 @@ RUNTIME_FUNCTION(Runtime_NewScriptContext) {
       FindNameClash(isolate, scope_info, global_object, script_context_table);
   if (isolate->has_pending_exception()) return name_clash_result;
 
-  // We do not need script contexts here during bootstrap.
-  DCHECK(!isolate->bootstrapper()->IsActive());
-
   Handle<Context> result =
       isolate->factory()->NewScriptContext(native_context, scope_info);
 

test/cctest/test-serialize.cc

@@ -3565,6 +3565,7 @@ UNINITIALIZED_TEST(SnapshotCreatorIncludeGlobalProxy) {
           base::make_unique<v8::Extension>("new extension",
                                            "function i() { return 24; }"
                                            "function j() { return 25; }"
+                                           "let a = 26;"
                                            "try {"
                                            "  if (o.p == 7) o.p++;"
                                            "} catch {}");
@@ -3582,6 +3583,7 @@ UNINITIALIZED_TEST(SnapshotCreatorIncludeGlobalProxy) {
         ExpectInt32("i()", 24);
         ExpectInt32("j()", 25);
         ExpectInt32("o.p", 8);
+        ExpectInt32("a", 26);
         v8::TryCatch try_catch(isolate);
         CHECK(CompileRun("x").IsEmpty());
         CHECK(try_catch.HasCaught());