ART: Modernize counting-down loops

Preparation for readability-implicit-bool-conversion.

Bug: 32619234
Test: WITH_TIDY=1 mmma art
Change-Id: I7a6f9636d5f4537020f99e8cf8560f7f6b6b7ba0
diff --git a/runtime/dex/dex_file_annotations.cc b/runtime/dex/dex_file_annotations.cc
index 51cfd43..b50a430 100644
--- a/runtime/dex/dex_file_annotations.cc
+++ b/runtime/dex/dex_file_annotations.cc
@@ -209,7 +209,7 @@
     case DexFile::kDexAnnotationArray:
     {
       uint32_t size = DecodeUnsignedLeb128(&annotation);
-      while (size--) {
+      for (; size != 0u; --size) {
         if (!SkipAnnotationValue(dex_file, &annotation)) {
           return false;
         }
@@ -221,7 +221,7 @@
     {
       DecodeUnsignedLeb128(&annotation);  // unused type_index
       uint32_t size = DecodeUnsignedLeb128(&annotation);
-      while (size--) {
+      for (; size != 0u; --size) {
         DecodeUnsignedLeb128(&annotation);  // unused element_name_index
         if (!SkipAnnotationValue(dex_file, &annotation)) {
           return false;