Uniform blocks members, when unnamed blocks are used, are
used in glsl only with the member's name, without any
reference to the block itself. When this happens, we still
need the whole block to be allocated as one contiguous
structure in the registers. To do that, whenever a member
of an unnamed block is first used, the whole block is
allocated. Also, whenever any member of an unnamed block
attempts to allocate a register, it first verifies if the
parent block has already been allocated. So this means that
both allocation and lookup must be done through the parent
block when dealing with unnamed block members.

Change-Id: Ib11eaa1ee052d32252f32997eb5f650a9765533d
Reviewed-on: https://swiftshader-review.googlesource.com/5059Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>