merge revision(s) 081ee3d3,1c97abaa: [Backport #19907] (#10315)

Add memory leak test for eval kwargs

	De-dup identical callinfo objects

	Previously every call to vm_ci_new (when the CI was not packable) would
	result in a different callinfo being returned this meant that every
	kwarg callsite had its own CI.

	When calling, different CIs result in different CCs. These CIs and CCs
	both end up persisted on the T_CLASS inside cc_tbl. So in an eval loop
	this resulted in a memory leak of both types of object. This also likely
	resulted in extra memory used, and extra time searching, in non-eval
	cases.

	For simplicity in this commit I always allocate a CI object inside
	rb_vm_ci_lookup, but ideally we would lazily allocate it only when
	needed. I hope to do that as a follow up in the future.