Revert "Use nullptr consistently in TIntermConstantUnion::fold" Part of a chain breaking the clang build: http://build.chromium.org/p/chromium.gpu.fyi/builders/GPU%20Linux%20Builder/builds/33588 This reverts commit 5f2feee42971fdbbd7cb389fffe2f632060ec6e3. Change-Id: I5ad54b05148ae2d4f19e50a67aded2bad4f55f91 Reviewed-on: https://chromium-review.googlesource.com/265143 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>