Update desugared library in third_party to 1.1.5

This updates the desugared library in third_party/openjdk/desugared_jdk_libs
to version 1.1.5 (https://github.com/google/desugar_jdk_libs/commit/793835fe272618b0086871ad70a1ffb80db749d1).

The JAR is built on the bot and copied from
gs://r8-releases/raw/desugar_jdk_libs/1.1.5/desugar_jdk_libs.jar by running:

  <edit third_party/openjdk/desugar_jdk_libs/README.google>
  export VERSION=1.1.5
  cd third_party/openjdk/
  gsutil.py cp gs://r8-releases/raw/desugar_jdk_libs/$VERSION/desugar_jdk_libs.jar desugar_jdk_libs
  upload_to_google_storage.py -a --bucket r8-deps desugar_jdk_libs

Content of README.google:

URL: https://github.com/google/desugar_jdk_libs
Version: 793835fe272618b0086871ad70a1ffb80db749d1
Revision: N/A
Date: Feb 24 2021
License: The GNU General Public License (GPL) (see LICENSE)

Description:
This project contains a small subset of OpenJDK libraries simplified for use on older runtimes.

Bug: 180903899
Change-Id: I7b614c3df2a956fef7668fc3c5fb01f9ec32a56a
diff --git a/third_party/openjdk/desugar_jdk_libs.tar.gz.sha1 b/third_party/openjdk/desugar_jdk_libs.tar.gz.sha1
index 5b0c632..c53b59b 100644
--- a/third_party/openjdk/desugar_jdk_libs.tar.gz.sha1
+++ b/third_party/openjdk/desugar_jdk_libs.tar.gz.sha1
@@ -1 +1 @@
-babe03fe1d812b8eddebfc3e9a1ea4add98d4647
\ No newline at end of file
+2e91f1ecbf04376cd0d8a9bd27615aa399f374c1
\ No newline at end of file