Avoid calls to deprecated GetIsolate methods

Use the stored isolate instead.

After this landed https://crrev.com/c/6613837 will advance the
deprecation of the methods in the V8 API.

Bug: 427885584

R=tsepez@chromium.org

Change-Id: I7ce29779f5de501ef56c60d5cfdd91772e056d8e
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/133910
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

fxjs/cjs_global.cpp

diff --git a/fxjs/cjs_global.cpp b/fxjs/cjs_global.cpp
index d2d52bc..af29d4c 100644
--- a/fxjs/cjs_global.cpp
+++ b/fxjs/cjs_global.cpp
@@ -515,7 +515,7 @@
         pTemp->sData = sData;
         break;
       case CFX_Value::DataType::kObject:
-        pTemp->pData.Reset(pData->GetIsolate(), pData);
+        pTemp->pData.Reset(GetRuntime()->GetIsolate(), pData);
         break;
       case CFX_Value::DataType::kNull:
         break;
@@ -542,7 +542,7 @@
       break;
     case CFX_Value::DataType::kObject:
       pNewData->nType = CFX_Value::DataType::kObject;
-      pNewData->pData.Reset(pData->GetIsolate(), pData);
+      pNewData->pData.Reset(GetRuntime()->GetIsolate(), pData);
       pNewData->bPersistent = bDefaultPersistent;
       break;
     case CFX_Value::DataType::kNull:

fxjs/cjs_object.cpp

diff --git a/fxjs/cjs_object.cpp b/fxjs/cjs_object.cpp
index da9184c..163d73f 100644
--- a/fxjs/cjs_object.cpp
+++ b/fxjs/cjs_object.cpp
@@ -41,7 +41,7 @@
 }
 
 CJS_Object::CJS_Object(v8::Local<v8::Object> pObject, CJS_Runtime* pRuntime)
-    : v8_object_(pObject->GetIsolate(), pObject), runtime_(pRuntime) {}
+    : v8_object_(pRuntime->GetIsolate(), pObject), runtime_(pRuntime) {}
 
 CJS_Object::CJS_Object(v8::Local<v8::Object> object, v8::Isolate* isolate)
     : v8_object_(isolate, object) {}