Fix implicit-fallthrough warning.

Bug: 112564944
Test: make checkbuild
Change-Id: Id5128b7fad1c267a6c9643817a146abb6949f237
diff --git a/tools/jfuzz/jfuzz.cc b/tools/jfuzz/jfuzz.cc
index a97a99c..b8a646d 100644
--- a/tools/jfuzz/jfuzz.cc
+++ b/tools/jfuzz/jfuzz.cc
@@ -562,11 +562,11 @@
       case 1:
         if (emitArrayVariable(tp))
           return;
-        // FALL-THROUGH
+        [[fallthrough]];
       case 2:
         if (emitLocalVariable(tp))
           return;
-        // FALL-THROUGH
+        [[fallthrough]];
       default:
         emitFieldVariable(tp);
         break;