chore: fix kokoro windows java 8 ci by setting JAVA11_HOME env variable (#2207)

* chore: fix kokoro windows java 8 ci by setting JAVA11_HOME env variable

Author: mpeddada1

.kokoro/build.bat

@@ -15,4 +15,7 @@
 :: downstream client libraries before they are released.
 :: See documentation in type-shell-output.bat
 
-"C:\Program Files\Git\bin\bash.exe" %~dp0build.sh
+choco install -y openjdk11
+set JAVA11_HOME=C:\Program Files\Eclipse Adoptium\jdk-11.0.17.8-hotspot\
+
+"C:\Program Files\Git\bin\bash.exe" %~dp0build.sh

owlbot.py

@@ -28,6 +28,7 @@
         ".kokoro/nightly/java8-samples.cfg",
         ".kokoro/nightly/java11-samples.cfg",
         ".kokoro/nightly/samples.cfg",
+        ".kokoro/build.bat",
         ".kokoro/presubmit/common.cfg",
         ".kokoro/presubmit/java8-samples.cfg",
         ".kokoro/presubmit/java11-samples.cfg",