GLSL ES 3.00 spec says that length is only allowed on "array names",
but according to
https://bugs.chromium.org/p/angleproject/issues/detail?id=2142 that
was not intended to be interpreted strictly and it has been clarified
in GLSL ES 3.20.

Change-Id: Id8944346908e1c122230fd2f94c9a26cf389498b
Reviewed-on: https://swiftshader-review.googlesource.com/15550Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>