Revert non-test changes in graphql#3442 , which introduced the bugged compareFragmentPairs usage

Author: sachindshinde

src/validation/rules/OverlappingFieldsCanBeMergedRule.ts

@@ -267,22 +267,6 @@ function collectConflictsBetweenFieldsAndFragment(
   // (E) Then collect any conflicts between the provided collection of fields
   // and any fragment names found in the given fragment.
   for (const referencedFragmentName of referencedFragmentNames) {
-    // Memoize so two fragments are not compared for conflicts more than once.
-    if (
-      comparedFragmentPairs.has(
-        referencedFragmentName,
-        fragmentName,
-        areMutuallyExclusive,
-      )
-    ) {
-      continue;
-    }
-    comparedFragmentPairs.add(
-      referencedFragmentName,
-      fragmentName,
-      areMutuallyExclusive,
-    );
-
     collectConflictsBetweenFieldsAndFragment(
       context,
       conflicts,