Add an assert in JitBlockCache

Core/MIPS/JitCommon/JitBlockCache.cpp

@@ -247,6 +247,8 @@ static void ExpandRange(std::pair<u32, u32> &range, u32 newStart, u32 newEnd) {
 void JitBlockCache::FinalizeBlock(int block_num, bool block_link) {
 	JitBlock &b = blocks_[block_num];
 
+	_assert_msg_(Memory::IsValidAddress(b.originalAddress), "FinalizeBlock: Bad originalAddress %08x in block %d", b.originalAddress, block_num);
+
 	b.originalFirstOpcode = Memory::Read_Opcode_JIT(b.originalAddress);
 	MIPSOpcode opcode = GetEmuHackOpForBlock(block_num);
 	Memory::Write_Opcode_JIT(b.originalAddress, opcode);