This reverts commit 59d982c0.

Reason for revert: crbug.com/1006501

Original change's description:
> Refactor built-in symbol table.
> 
> In preparation for reducing binary size. Shortend a bunch of strings
> and symbol prefixes so the autogen file will be more compact.
> 
> Bug: chromium:998535
> Change-Id: If1bedaaacc06dce9678d432055ffa0c9215a8dbd
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1814724
> Reviewed-by: Tim Van Patten <timvp@google.com>
> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

TBR=timvp@google.com,jonahr@google.com,jmadill@chromium.org

Change-Id: Ie540da8ea4429e075a3284183e5a004cbcf1307b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:998535,chromium:1006501
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1817497Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Zhenyao Mo <zmo@chromium.org>