Fix vertical fallback space sign

Ouch!

Follow-up to cf203af8a33591c163b63dbdf0fd341bc4606190

Fixes https://github.com/harfbuzz/harfbuzz/issues/1343
diff --git a/src/hb-ot-shape-fallback.cc b/src/hb-ot-shape-fallback.cc
index bbc410a..d3afdff 100644
--- a/src/hb-ot-shape-fallback.cc
+++ b/src/hb-ot-shape-fallback.cc
@@ -509,16 +509,16 @@
 	case t::SPACE_EM_6:
 	case t::SPACE_EM_16:
 	  if (horizontal)
-	    pos[i].x_advance = (font->x_scale + ((int) space_type)/2) / (int) space_type;
+	    pos[i].x_advance = +(font->x_scale + ((int) space_type)/2) / (int) space_type;
 	  else
-	    pos[i].y_advance = (font->y_scale + ((int) space_type)/2) / (int) space_type;
+	    pos[i].y_advance = -(font->y_scale + ((int) space_type)/2) / (int) space_type;
 	  break;
 
 	case t::SPACE_4_EM_18:
 	  if (horizontal)
-	    pos[i].x_advance = (int64_t) font->x_scale * 4 / 18;
+	    pos[i].x_advance = (int64_t) +font->x_scale * 4 / 18;
 	  else
-	    pos[i].y_advance = (int64_t) font->y_scale * 4 / 18;
+	    pos[i].y_advance = (int64_t) -font->y_scale * 4 / 18;
 	  break;
 
 	case t::SPACE_FIGURE:
diff --git a/test/shaping/data/in-house/tests/spaces.tests b/test/shaping/data/in-house/tests/spaces.tests
index 526d158..ea90998 100644
--- a/test/shaping/data/in-house/tests/spaces.tests
+++ b/test/shaping/data/in-house/tests/spaces.tests
@@ -18,17 +18,17 @@
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+0020:[gid1=0@-280,0+0,-2048]
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+00A0:[gid1=0@-280,0+0,-2048]
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+1680:[gid0=0@-346,0+0,-2048]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2000:[gid1=0@-280,0+0,1024]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2001:[gid1=0@-280,0+0,2048]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2002:[gid1=0@-280,0+0,1024]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2003:[gid1=0@-280,0+0,2048]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2004:[gid1=0@-280,0+0,683]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2005:[gid1=0@-280,0+0,512]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2006:[gid1=0@-280,0+0,341]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2000:[gid1=0@-280,0+0,-1024]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2001:[gid1=0@-280,0+0,-2048]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2002:[gid1=0@-280,0+0,-1024]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2003:[gid1=0@-280,0+0,-2048]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2004:[gid1=0@-280,0+0,-683]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2005:[gid1=0@-280,0+0,-512]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2006:[gid1=0@-280,0+0,-341]
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2007:[gid1=0@-280,0+0,-2048]
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2008:[gid1=0@-280,0+0,-2048]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2009:[gid1=0@-280,0+0,410]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+200A:[gid1=0@-280,0+0,128]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+2009:[gid1=0@-280,0+0,-410]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+200A:[gid1=0@-280,0+0,-128]
 ../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+202F:[gid1=0@-280,0+0,-1024]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+205F:[gid1=0@-280,0+0,455]
-../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+3000:[gid1=0@-280,0+0,2048]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+205F:[gid1=0@-280,0+0,-455]
+../fonts/1c2c3fc37b2d4c3cb2ef726c6cdaaabd4b7f3eb9.ttf:--font-funcs=ot --direction=ttb:U+3000:[gid1=0@-280,0+0,-2048]