[inspector] Add support for the RegExp `d` flag

Prior to this patch, the RemoteObject for e.g. `/x/d` got a
`description` that omitted the new `d` (`hasIndices`) flag.

Bug: v8:11684, v8:9548
Change-Id: I774fbd9620c6f3f2f19b819c9009fab7cc2e3229
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2848460Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74148}

src/inspector/value-mirror.cc

@@ -202,6 +202,7 @@ String16 descriptionForRegExp(v8::Isolate* isolate,
   description.append(toProtocolString(isolate, value->GetSource()));
   description.append('/');
   v8::RegExp::Flags flags = value->GetFlags();
+  if (flags & v8::RegExp::Flags::kHasIndices) description.append('d');
   if (flags & v8::RegExp::Flags::kGlobal) description.append('g');
   if (flags & v8::RegExp::Flags::kIgnoreCase) description.append('i');
   if (flags & v8::RegExp::Flags::kLinear) description.append('l');

test/inspector/runtime/remote-object-expected.txt

@@ -397,6 +397,16 @@ Running test: testBigInt
 }
 
 Running test: testRegExp
+'/w+/d', returnByValue: false, generatePreview: false
+{
+    result : {
+        className : RegExp
+        description : /w+/d
+        objectId : <objectId>
+        subtype : regexp
+        type : object
+    }
+}
 '/w+/g', returnByValue: false, generatePreview: false
 {
     result : {
@@ -457,11 +467,11 @@ Running test: testRegExp
         type : object
     }
 }
-'/w+/gimsuy', returnByValue: false, generatePreview: false
+'/w+/dgimsuy', returnByValue: false, generatePreview: false
 {
     result : {
         className : RegExp
-        description : /w+/gimsuy
+        description : /w+/dgimsuy
         objectId : <objectId>
         subtype : regexp
         type : object

test/inspector/runtime/remote-object.js

@@ -200,6 +200,9 @@ InspectorTest.runAsyncTestSuite([
     })).result);
   },
   async function testRegExp() {
+    InspectorTest.logMessage((await evaluate({
+      expression: '/\w+/d'
+    })).result);
     InspectorTest.logMessage((await evaluate({
       expression: '/\w+/g'
     })).result);
@@ -219,7 +222,7 @@ InspectorTest.runAsyncTestSuite([
       expression: '/\w+/y'
     })).result);
     InspectorTest.logMessage((await evaluate({
-      expression: '/\w+/gimsuy'
+      expression: '/\w+/dgimsuy'
     })).result);
     InspectorTest.logMessage((await evaluate({
       expression: `new RegExp('\\w+', 'g')`,