[ConstraintSystem] Remove default argument for updateWorkList from

ConstraintSystem::mergeEquivalenceClasses.

Most callers don't use the default, and it's important to consider
the value of this argument for each call to mergeEquivalenceClasses.

Author: hborla

lib/Sema/CSSimplify.cpp

@@ -4529,7 +4529,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
           return formUnsolvedResult();
 
         // Merge the equivalence classes corresponding to these two variables.
-        mergeEquivalenceClasses(rep1, rep2);
+        mergeEquivalenceClasses(rep1, rep2, /*updateWorkList=*/true);
         return getTypeMatchSuccess();
       }
 
@@ -4581,7 +4581,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
         if (!rep1->getImpl().canBindToInOut() ||
             !rep2->getImpl().canBindToLValue()) {
           // Merge the equivalence classes corresponding to these two variables.
-          mergeEquivalenceClasses(rep1, rep2);
+          mergeEquivalenceClasses(rep1, rep2, /*updateWorkList=*/true);
           return getTypeMatchSuccess();
         }
       }

lib/Sema/ConstraintSystem.h

@@ -3443,7 +3443,7 @@ class ConstraintSystem {
   /// distinct.
   void mergeEquivalenceClasses(TypeVariableType *typeVar1,
                                TypeVariableType *typeVar2,
-                               bool updateWorkList = true);
+                               bool updateWorkList);
 
   /// Flags that direct type matching.
   enum TypeMatchFlags {