pdfium_test: exit cleanly if V8 snapshot files not found.

Bug: pdfium:1616
Change-Id: Ib4093f8d1220460acd6a00de7884d5a36f635710
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/76270
Reviewed-by: Hui Yingst <nigi@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index ee7b41c..91b4f90 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -1176,6 +1176,10 @@
 #else   // V8_USE_EXTERNAL_STARTUP_DATA
     platform = InitializeV8ForPDFium(options.exe_path, options.js_flags);
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
+    if (!platform) {
+      fprintf(stderr, "V8 initialization failed.\n");
+      return 1;
+    }
     config.m_pPlatform = platform.get();
 
     v8::Isolate::CreateParams params;