Debugger: Avoid unaligned reads in expressions.

Potentially, a watch or break condition could crash if it was unaligned
between mirrors.  This might happen if it's not the condition you wanted,
especially.  Play it safe.

Core/MIPS/MIPSDebugInterface.cpp

@@ -162,17 +162,20 @@ public:
 	bool getMemoryValue(uint32_t address, int size, uint32_t& dest, char* error) override {
 		// We allow, but ignore, bad access.
 		// If we didn't, log/condition statements that reference registers couldn't be configured.
-		bool valid = Memory::IsValidRange(address, size);
+		uint32_t valid = Memory::ValidSize(address, size);
+		uint8_t buf[4]{};
+		if (valid != 0)
+			memcpy(buf, Memory::GetPointerUnchecked(address), valid);
 
 		switch (size) {
 		case 1:
-			dest = valid ? Memory::Read_U8(address) : 0;
+			dest = buf[0];
 			return true;
 		case 2:
-			dest = valid ? Memory::Read_U16(address) : 0;
+			dest = (buf[1] << 8) | buf[0];
 			return true;
 		case 4:
-			dest = valid ? Memory::Read_U32(address) : 0;
+			dest = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 			return true;
 		}
 
@@ -196,9 +199,10 @@ const char *MIPSDebugInterface::disasm(unsigned int address, unsigned int align)
 	return mojs;
 }
 
-unsigned int MIPSDebugInterface::readMemory(unsigned int address)
-{
-	return Memory::Read_Instruction(address).encoding;
+unsigned int MIPSDebugInterface::readMemory(unsigned int address) {
+	if (Memory::IsValidRange(address, 4))
+		return Memory::ReadUnchecked_Instruction(address).encoding;
+	return 0;
 }
 
 bool MIPSDebugInterface::isAlive()