[Diagnostics] NFC: ConstraintFix::{print, dump} no longer need SourceManager passed-in

Since `ConstraintFix` references `ConstraintSystem` directly now,
we can get `SourceManager` from `ASTContext` associated with that
`ConstraintSystem` instead of passing it in every time.

lib/Sema/CSSimplify.cpp

@@ -4988,7 +4988,7 @@ bool ConstraintSystem::recordFix(ConstraintFix *fix) {
     auto &log = ctx.TypeCheckerDebug->getStream();
     log.indent(solverState ? solverState->depth * 2 + 2 : 0)
       << "(attempting fix ";
-    fix->print(log, &ctx.SourceMgr);
+    fix->print(log);
     log << ")\n";
   }