remove old way of overriding env var which is now deprecated

std-bits/base/src/main/java/org/enso/base/Environment_Utils.java

@@ -14,32 +14,6 @@ public static String get_environment_variable(String name) {
     }
   }
 
-  /**
-   * Calls `action` with the provided environment variable.
-   *
-   * <p>The override is not persisted (its only visible from within the action called by this
-   * method) and it is only visible by the Enso `Environment.get` method (backed by {@code
-   * get_environment_variable}).
-   *
-   * <p>This is an internal function that should be used very carefully and only for testing.
-   */
-  public static <T> T with_environment_variable_override(
-      String name, String value, Function<Object, T> action) {
-    String oldValue = overrides.put(name, value);
-    boolean was_set = oldValue != null;
-    try {
-      // Giving 0 here as an argument, as using null would lead to incorrect behaviour, due to some
-      // weird Truffle peculiarity.
-      return action.apply(0);
-    } finally {
-      if (was_set) {
-        overrides.put(name, oldValue);
-      } else {
-        overrides.remove(name);
-      }
-    }
-  }
-
   public static void setOverride(String name, String value) {
     overrides.put(name, value);
   }