subtype: don't re-select constraintkind 1 for vars bounding inner vars

[adienes]

I think this needs to match the check above with never_occurs_in_inside_ub before setting constraintkind=1

julia/src/subtype.c

Lines 5334 to 5335 in 4cecb80

	// Setting constraintkind=1 for covariant var might be invalid if it also occurs in triangular positions.
	if (is_leaf_typevar(u->var) && noinv && always_occurs_cov(u->body, u->var, param) && never_occurs_in_inside_ub(u->body, u->var))

also fixes a test case that tests the bug (witness: Tuple{Tuple{Int8},Tuple{Int},Int})

Assisted-by: Claude Code (Opus 5.5)