Fix assertion-violations on non-integers

These bugs were introduced after bignums were added.
* src/data.c (cons_to_unsigned, cons_to_signed):
* src/xdisp.c (calc_line_height_property):
Invoke integer_to_intmax and integer_to_uintmax only on integers.

src/data.c

@@ -2655,7 +2655,7 @@ cons_to_unsigned (Lisp_Object c, uintmax_t max)
   else
     {
       Lisp_Object hi = CONSP (c) ? XCAR (c) : c;
-      valid = integer_to_uintmax (hi, &val);
+      valid = INTEGERP (hi) && integer_to_uintmax (hi, &val);
 
       if (valid && CONSP (c))
 	{
@@ -2716,7 +2716,7 @@ cons_to_signed (Lisp_Object c, intmax_t min, intmax_t max)
   else
     {
       Lisp_Object hi = CONSP (c) ? XCAR (c) : c;
-      valid = integer_to_intmax (hi, &val);
+      valid = INTEGERP (hi) && integer_to_intmax (hi, &val);
 
       if (valid && CONSP (c))
 	{

src/xdisp.c

@@ -27991,7 +27991,7 @@ calc_line_height_property (struct it *it, Lisp_Object val, struct font *font,
   /* FIXME: Check for overflow in multiplication or conversion.  */
   if (FLOATP (val))
     height = (int)(XFLOAT_DATA (val) * height);
-  else
+  else if (INTEGERP (val))
     {
       intmax_t v;
       if (integer_to_intmax (val, &v))