Includes:

    Update OpPhi instructions after splitting block. (#1783)
    Don't change decorations and names in merge return. (#1777)
    Transform to combine consecutive access chains
    Handle undef literal value in vector shuffle
    Fix block ordering in dead branch elim
    Fix finding constant with particular type. (#1724)
    Fix infinite loop while folding OpVectorShuffle (#1722)
    Fix size error when folding vector shuffle. (#1721)
    Layout validation: Permit {vec3; float} tight packing