Fix use-after-delete in ParseContext.cpp.
Fix use-after-delete in ParseContext.cpp.

This bug was exposed after a refactoring from the translator.

BUG=None
TEST=angle_unittests,angle_end2end_tests

Change-Id: I13fddcbe84f87826068a557f139f6e35c674571e
Reviewed-on: https://chromium-review.googlesource.com/287832
Reviewed-by: Zhenyao Mo <655bdf1d95ff956cd68886dd9e86ee5e987c9dbb@chromium.org>
Tested-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

mybios/angle,mybios/angle,crezefire/angle,ecoal95/angle,ppy/angle,mikolalysenko/angle,ppy/angle,vvuk/angle,csa7mdm/angle,larsbergstrom/angle,bsergean/angle,ecoal95/angle,MSOpenTech/angle,ppy/angle,bsergean/angle,bsergean/angle,ecoal95/angle,mikolalysenko/angle,csa7mdm/angle,ppy/angle,crezefire/angle,csa7mdm/angle,mlfarrell/angle,mlfarrell/angle,mybios/angle,domokit/waterfall,vvuk/angle,ecoal95/angle,mlfarrell/angle,vvuk/angle,MSOpenTech/angle,MSOpenTech/angle,larsbergstrom/angle,larsbergstrom/angle,MSOpenTech/angle,mikolalysenko/angle,mikolalysenko/angle,bsergean/angle,csa7mdm/angle,vvuk/angle,larsbergstrom/angle,mlfarrell/angle,ecoal95/angle,crezefire/angle,crezefire/angle,mybios/angle,domokit/waterfall