Add java8 runtime option to all non-production appengine-web*.xml files

Java 8 is go!

https://cloudplatform.googleblog.com/2017/09/Java-8-on-App-Engine-Standard-environment-is-now-generally-available.html

We will add this option to the production files next week.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=170101056

java/google/registry/env/alpha/backend/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/alpha/default/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/alpha/tools/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/crash/backend/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/crash/default/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/crash/tools/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/local/backend/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/local/default/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/local/tools/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/sandbox/backend/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/sandbox/default/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>

java/google/registry/env/sandbox/tools/WEB-INF/appengine-web.xml

@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>