deps: cherry-pick 09de996 from V8 upstream

Original commit message:
  [debugger] fix switch block source positions.

  The switch statement itself is part of the switch block.
  However, the source position of the statement is outside of
  the block. This leads to confusion for the debugger, if the
  switch block pushes a block context: the current context is
  a block context, but the scope analysis based on the current
  source position tells the debugger that we should be outside
  the scope, so we should have the function context.

  R=marja@chromium.org
  BUG=v8:6085
  Review-Url: https://codereview.chromium.org/2744213003
  Cr-Commit-Position: refs/heads/master@{#43744}
  Committed: https://chromium.googlesource.com/v8/v8/+/09de9969ccb9bc3bbd667788afad665b309d02f5

Fixes: #11746

deps/v8/include/v8-version.h

@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 5
 #define V8_MINOR_VERSION 6
 #define V8_BUILD_NUMBER 326
-#define V8_PATCH_LEVEL 56
+#define V8_PATCH_LEVEL 57
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)

deps/v8/src/parsing/parser-base.h

@@ -5008,7 +5008,7 @@ typename ParserBase<Impl>::StatementT ParserBase<Impl>::ParseSwitchStatement(
 
   {
     BlockState cases_block_state(zone(), &scope_state_);
-    cases_block_state.set_start_position(scanner()->location().beg_pos);
+    cases_block_state.set_start_position(switch_pos);
     cases_block_state.SetNonlinear();
     typename Types::Target target(this, switch_statement);
 

deps/v8/src/parsing/parser.cc

@@ -1729,6 +1729,10 @@ Statement* Parser::RewriteSwitchStatement(Expression* tag,
   Block* cases_block = factory()->NewBlock(NULL, 1, false, kNoSourcePosition);
   cases_block->statements()->Add(switch_statement, zone());
   cases_block->set_scope(scope);
+  DCHECK_IMPLIES(scope != nullptr,
+                 switch_statement->position() >= scope->start_position());
+  DCHECK_IMPLIES(scope != nullptr,
+                 switch_statement->position() < scope->end_position());
   switch_block->statements()->Add(cases_block, zone());
   return switch_block;
 }

deps/v8/test/debugger/regress/regress-6085.js

@@ -0,0 +1,49 @@
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function* serialize() {
+  debugger;
+  switch (0) {
+    case 0:
+      let x = 1;
+      return x;  // Check scopes
+  }
+}
+
+let exception = null;
+let step_count = 0;
+let scopes_checked = false;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    if (exec_state.frame().sourceLineText().includes("Check scopes")) {
+      let expected = [ debug.ScopeType.Block,
+                       debug.ScopeType.Local,
+                       debug.ScopeType.Script,
+                       debug.ScopeType.Global ];
+      for (let i = 0; i < exec_state.frame().scopeCount(); i++) {
+        assertEquals(expected[i], exec_state.frame().scope(i).scopeType());
+      }
+      scopes_checked = true;
+    }
+    if (step_count++ < 3) exec_state.prepareStep(Debug.StepAction.StepNext);
+  } catch (e) {
+    exception = e;
+    print(e, e.stack);
+  }
+}
+
+
+
+let Debug = debug.Debug;
+Debug.setListener(listener);
+
+let gen = serialize();
+gen.next();
+
+Debug.setListener(null);
+assertNull(exception);
+assertEquals(4, step_count);
+assertTrue(scopes_checked);