Add inactive buildvariant for running tests against latest server (#2982)

* Add inactive buildvariant for running tests against latest server

* remove unnecessary axis change

* use a less ambiguous name

* don't test with FLE (python issues during launch)

Author: jamis

.evergreen/config.yml

@@ -1571,6 +1571,18 @@ buildvariants:
 #    tasks:
 #      - name: "test-fle"
 
+  - name: 'latest-server'
+    activate: false
+    display_name: 'Latest MongoDB Server'
+    run_on: ubuntu2204-small
+    expansions:
+      TOPOLOGY: sharded_cluster
+      MLAUNCH_TOPOLOGY: sharded-cluster
+      RVM_RUBY: "ruby-4.0"
+      MONGODB_VERSION: 'latest'
+    tasks:
+      - name: 'run-main-test-suite'
+
   - matrix_name: aws-auth-regular
     matrix_spec:
       # https://jira.mongodb.org/browse/RUBY-3311

.evergreen/config/standard.yml.erb

@@ -29,7 +29,6 @@
   # The latest stable version of MongoDB
   latest_stable_mdb = "8.0".inspect # so it gets quoted as a string
 
-
   recent_mdb = %w( 8.0 7.0 )
 %>
 
@@ -379,6 +378,18 @@ buildvariants:
 #    tasks:
 #      - name: "test-fle"
 
+  - name: 'latest-server'
+    activate: false
+    display_name: 'Latest MongoDB Server'
+    run_on: ubuntu2204-small
+    expansions:
+      TOPOLOGY: sharded_cluster
+      MLAUNCH_TOPOLOGY: sharded-cluster
+      RVM_RUBY: <%= latest_ruby %>
+      MONGODB_VERSION: 'latest'
+    tasks:
+      - name: 'run-main-test-suite'
+
   - matrix_name: aws-auth-regular
     matrix_spec:
       # https://jira.mongodb.org/browse/RUBY-3311