bug fix

Author: Ruihan-Yin

src/coreclr/jit/instr.h

@@ -219,7 +219,7 @@ enum insFlags : uint64_t
     INS_Flags_EmbeddedBroadcastSupported = 1ULL << 43,
 
     // APX: REX2 prefix:
-    Encoding_REX2  = 1ULL << 43,
+    Encoding_REX2  = 1ULL << 44,
 
     //  TODO-Cleanup:  Remove this flag and its usage from TARGET_XARCH
     INS_FLAGS_DONT_CARE = 0x00ULL,