Delete README.angle from googletest.

This file is a bit odd. It doesn't belong in this folder.

Bug: angleproject:3986
Change-Id: Idf783e469a679a73f900bb20093e7e339fab9301
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1864312
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

third_party/googletest/README.angle

@@ -1,7 +0,0 @@
-Name: Google Test: Google's C++ Testing Framework
-Short Name: googletest
-URL: https://github.com/google/googletest.git
-Version: 1.8.0.git-7f8fefabedf2965980585be8c2bff97458f28e0b
-License: BSD
-License File: NOT_SHIPPED
-Security critical: no