When multiple instances of the same attribute are provided, CTS expects
the last instance to win. Achieve this by:
	1/ Reducing the attribute list in getConfigs()
	2/ Adjusting the sort order's consideration of which color
	components are "required" to allow a later 0 or EGL_DONT_CARE to
	remove a component from consideration again.

Affects: dEQP-EGL.functional.choose_config.*
Bug: b/113679786

V2: Fix up the alignment I broke
V4: Style fix

Change-Id: If9375c9dc5aaadb0ee7b77ecf1e1098c82fa30ca
Reviewed-on: https://swiftshader-review.googlesource.com/20448Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Chris Forbes <chrisforbes@google.com>