Make aggregate node creation more robust Now aggregate nodes are always built with their return type, op and arguments set. They'll determine their qualifier and precision automatically. This fixes setting of gotPrecisionFromChildren in a few cases. This will also make it easier to split TIntermAggregate further into specialized classes if that is desired. BUG=angleproject:1490 TEST=angle_unittests Change-Id: I1fbe0c75679c517a22d44dfc1ea160ad7a7fdfda Reviewed-on: https://chromium-review.googlesource.com/433468 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>