Fix testAndBranch sign extend to 64 bit (#1213)

diff --git a/arch/AArch64/AArch64Disassembler.c b/arch/AArch64/AArch64Disassembler.c
index d4d548d..e69ff17 100644
--- a/arch/AArch64/AArch64Disassembler.c
+++ b/arch/AArch64/AArch64Disassembler.c
@@ -1635,7 +1635,7 @@
 {
 	uint32_t Rt = fieldFromInstruction(insn, 0, 5);
 	uint32_t bit = fieldFromInstruction(insn, 31, 1) << 5;
-	uint32_t dst = fieldFromInstruction(insn, 5, 14);
+	uint64_t dst = fieldFromInstruction(insn, 5, 14);
 
 	bit |= fieldFromInstruction(insn, 19, 5);