Jit64: Faster linking of continuous blocks

We compile the blocks as they are executed, so it's common
to link them continuously. We end with calling JMP after every
block, but often just with a distance of 0.
So just emitting NOPs instead also "calls" the next block, but
easier for the CPU.

Source/Core/Core/PowerPC/JitCommon/JitCache.cpp

@@ -324,9 +324,20 @@ using namespace Gen;
 	{
 		XEmitter emit(location);
 		if (*location == 0xE8)
+		{
 			emit.CALL(address);
+		}
 		else
-			emit.JMP(address, true);
+		{
+			// If we're going to link with the next block, there is no need
+			// to emit JMP. So just NOP out the gap to the next block.
+			// Support up to 3 additional bytes because of alignment.
+			s64 offset = address - emit.GetCodePtr();
+			if (offset > 0 && offset <= 5 + 3)
+				emit.NOP(offset);
+			else
+				emit.JMP(address, true);
+		}
 	}
 
 	void JitBlockCache::WriteDestroyBlock(const u8* location, u32 address)