Fix the error message for when an erroneous HLSL constructor statement
is detected.
Prior to this change, such error messages would not show correct file
path and line number information.
Additionally, update test data to account for updated error messages.
This implements mytex.mips[mip][coord] for texture types. There is
some error testing, but not comprehensive. The constructs can be
nested, e.g in this case the inner .mips is parsed before the completion
of the outer [][] operator.
tx.mips[tx.mips[a][b].x][c]
