fix: check ftell() return value to prevent SIZE_MAX allocation

ftell() returns -1 on failure, which when cast to size_t becomes
SIZE_MAX, causing new char[SIZE_MAX] to crash. Added return value
check and early return with empty result on failure.

Signed-off-by: Srikanth Patchava <spatchava@meta.com>
Signed-off-by: Srikanth Patchava <srikanth.patchava@outlook.com>

googletest/src/gtest-port.cc

@@ -1258,7 +1258,11 @@ std::string GetCapturedStderr() {
 
 size_t GetFileSize(FILE* file) {
   fseek(file, 0, SEEK_END);
-  return static_cast<size_t>(ftell(file));
+  const long size = ftell(file);
+  if (size < 0) {
+    return 0;
+  }
+  return static_cast<size_t>(size);
 }
 
 std::string ReadEntireFile(FILE* file) {