[region-isolation] Add a small helper to TrackableValue to print it's isolation info.

I am finding that I am calling that a bunch so this just makes it a little more
convenient.

Author: gottesmm

include/swift/SILOptimizer/Analysis/RegionAnalysis.h

@@ -289,6 +289,11 @@ class regionanalysisimpl::TrackableValue {
   /// parameter.
   bool isTransferringParameter() const;
 
+  void printIsolationInfo(SmallString<64> &outString) const {
+    llvm::raw_svector_ostream os(outString);
+    getIsolationRegionInfo().printForDiagnostics(os);
+  }
+
   void print(llvm::raw_ostream &os) const {
     os << "TrackableValue. State: ";
     valueState.print(os);