Add missed null check in ClassLoaderContext::VerifyClassLoaderContextMatch.

bug: 119441748
Test: class_loader_context_test
Change-Id: I68301a568eb321b42209584a3328e9a1b0fcc7ba
diff --git a/runtime/class_loader_context.cc b/runtime/class_loader_context.cc
index de9fe22..0bae60a 100644
--- a/runtime/class_loader_context.cc
+++ b/runtime/class_loader_context.cc
@@ -338,6 +338,7 @@
   // no dex files. So that we can distinguish the real failures...
   const ArtDexFileLoader dex_file_loader;
   std::vector<ClassLoaderInfo*> work_list;
+  CHECK(class_loader_chain_ != nullptr);
   work_list.push_back(class_loader_chain_.get());
   while (!work_list.empty()) {
     ClassLoaderInfo* info = work_list.back();
@@ -908,7 +909,9 @@
   // collision check.
   if (expected_context.special_shared_library_) {
     // Special case where we are the only entry in the class path.
-    if (class_loader_chain_->parent == nullptr && class_loader_chain_->classpath.size() == 0) {
+    if (class_loader_chain_ != nullptr &&
+        class_loader_chain_->parent == nullptr &&
+        class_loader_chain_->classpath.size() == 0) {
       return VerificationResult::kVerifies;
     }
     return VerificationResult::kForcedToSkipChecks;