Check string size before using strlen

Otherwise, if the string is shorter than 'cdex'
we will have a heap-buffer-overflow.

Bug: 282186582
Test: Run the fuzzer locally with a 2 byte file
Change-Id: Iaa8baae926ae6c1d4ee6b7772489e8382618f79b
diff --git a/tools/fuzzer/libart_verify_dex_fuzzer.cc b/tools/fuzzer/libart_verify_dex_fuzzer.cc
index 718e3df..8c57da3 100644
--- a/tools/fuzzer/libart_verify_dex_fuzzer.cc
+++ b/tools/fuzzer/libart_verify_dex_fuzzer.cc
@@ -31,7 +31,8 @@
   // Skip compact DEX.
   // TODO(dsrbecky): Remove after removing compact DEX.
   const char* dex_string = "cdex";
-  if (strncmp(dex_string, (const char*)data, strlen(dex_string)) == 0) {
+  if (size >= strlen(dex_string) &&
+      strncmp(dex_string, (const char*)data, strlen(dex_string)) == 0) {
     // A -1 indicates we don't want this DEX added to the corpus.
     return -1;
   }