Improve the rendering in MGS3 (even if the game is still broken
due to others TC issues)
// Typical bug (MGS3 blue cloud):
// 1/ RT used as 32 bits => alpha channel written
// 2/ RT used as 24 bits => no update of alpha channel
// 3/ Lookup of texture that used alpha channel as index, HasSharedBits will return false
// because of the previous draw call format
//
// Solution: consider the RT as 32 bits if the alpha was used in the past
Gregory Hainaut
85543db094