Rationalize prod/sandbox instance numbers to 50/5/50

That's 50 each for frontend and backend and 5 for tools. Since the
MetricExporter bug has been fixed for awhile now, we aren't gaining anything by
artificially keeping the instance number low, whereas we might benefit from
higher instance counts, e.g. for load-testing.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=179432038

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

@@ -9,7 +9,7 @@
   <sessions-enabled>true</sessions-enabled>
   <instance-class>B4_1G</instance-class>
   <basic-scaling>
-    <max-instances>8</max-instances>
+    <max-instances>50</max-instances>
     <idle-timeout>30m</idle-timeout>
   </basic-scaling>
 

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

@@ -9,7 +9,7 @@
   <sessions-enabled>true</sessions-enabled>
   <instance-class>B4_1G</instance-class>
   <basic-scaling>
-    <max-instances>50</max-instances>
+    <max-instances>5</max-instances>
     <idle-timeout>10m</idle-timeout>
   </basic-scaling>
 

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

@@ -9,7 +9,7 @@
   <sessions-enabled>true</sessions-enabled>
   <instance-class>B4</instance-class>
   <basic-scaling>
-    <max-instances>8</max-instances>
+    <max-instances>50</max-instances>
     <idle-timeout>10m</idle-timeout>
   </basic-scaling>
 

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

@@ -9,7 +9,7 @@
   <sessions-enabled>true</sessions-enabled>
   <instance-class>B4</instance-class>
   <basic-scaling>
-    <max-instances>8</max-instances>
+    <max-instances>50</max-instances>
     <idle-timeout>30m</idle-timeout>
   </basic-scaling>
 

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

@@ -9,7 +9,7 @@
   <sessions-enabled>true</sessions-enabled>
   <instance-class>B4</instance-class>
   <basic-scaling>
-    <max-instances>2</max-instances>
+    <max-instances>5</max-instances>
     <idle-timeout>10m</idle-timeout>
   </basic-scaling>