Fix initialziation of XFA fuzzers against CPPGC heap.

Requires a non-null platform using v3 config.

Bug: chromium:1119533
Change-Id: I2afe90809ca9e4c3c7713259c7e21f6e3a7b6c4e
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/72990
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

testing/fuzzers/pdf_fuzzer_init_public.cc

diff --git a/testing/fuzzers/pdf_fuzzer_init_public.cc b/testing/fuzzers/pdf_fuzzer_init_public.cc
index 0ced636..ad39e36 100644
--- a/testing/fuzzers/pdf_fuzzer_init_public.cc
+++ b/testing/fuzzers/pdf_fuzzer_init_public.cc
@@ -69,10 +69,13 @@
 #endif  // PDF_ENABLE_V8
 
     memset(&config, '\0', sizeof(config));
-    config.version = 2;
+    config.version = 3;
     config.m_pUserFontPaths = nullptr;
     config.m_pIsolate = nullptr;
     config.m_v8EmbedderSlot = 0;
+#ifdef PDF_ENABLE_V8
+    config.m_pPlatform = platform.get();
+#endif  // PDF_ENABLE_V8
     FPDF_InitLibraryWithConfig(&config);
 
     memset(&unsupport_info, '\0', sizeof(unsupport_info));