enable multi-option context support

#53876

Change-Id: Ia6e8fd299685f6049862a7027e9c7734d806e328
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/350342
Commit-Queue: Phil Quitslund <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

pkg/analyzer/lib/src/dart/analysis/context_locator.dart

@@ -31,7 +31,7 @@ class ContextLocatorImpl implements ContextLocator {
   /// analysis options file.
   ///
   /// See: https://github.com/dart-lang/sdk/issues/53876
-  static bool singleOptionContexts = true;
+  static bool singleOptionContexts = false;
 
   /// The resource provider used to access the file system.
   final ResourceProvider resourceProvider;