[MemProf] Print internal context id when reporting bytes hinted (#128188)

During the whole program reporting of contexts when hinted byte
reporting is enabled via -memprof-report-hinted-sizes, also print the
internal context id. This is useful for debugging, as well as for
guiding the dot file dumping with some upcoming changes that will
accept a context id to focus the graph on a context of interest.

Author: teresajohnson

llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp

@@ -2957,6 +2957,8 @@ void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::printTotalSizes(
           if (allocTypeToUse(Node->AllocTypes) != AllocTypeFromCall)
             OS << " marked " << getAllocTypeString((uint8_t)AllocTypeFromCall)
                << " due to cold byte percent";
+          // Print the internal context id to aid debugging and visualization.
+          OS << " (context id " << Id << ")";
           OS << "\n";
         }
       }

llvm/test/ThinLTO/X86/memprof-basic.ll

@@ -273,9 +273,9 @@ attributes #0 = { noinline optnone }
 ; DUMP: 		Edge from Callee [[BAR2]] to Caller: [[BAZ2]] AllocTypes: Cold ContextIds: 2
 ; DUMP:		Clone of [[BAR]]
 
-; SIZES: NotCold full allocation context 123 with total size 100 is NotCold after cloning
-; SIZES: Cold full allocation context 456 with total size 200 is Cold after cloning
-; SIZES: Cold full allocation context 789 with total size 300 is Cold after cloning
+; SIZES: NotCold full allocation context 123 with total size 100 is NotCold after cloning (context id 1)
+; SIZES: Cold full allocation context 456 with total size 200 is Cold after cloning (context id 2)
+; SIZES: Cold full allocation context 789 with total size 300 is Cold after cloning (context id 2)
 
 ; REMARKS: call in clone main assigned to call function clone _Z3foov.memprof.1
 ; REMARKS: created clone _Z3barv.memprof.1

llvm/test/Transforms/MemProfContextDisambiguation/basic.ll

@@ -252,9 +252,9 @@ attributes #6 = { builtin }
 ; REMARKS: call in clone _Z3bazv assigned to call function clone _Z3barv
 ; REMARKS: call in clone _Z3barv marked with memprof allocation attribute notcold
 
-; SIZES: NotCold full allocation context 123 with total size 100 is NotCold after cloning
-; SIZES: Cold full allocation context 456 with total size 200 is Cold after cloning
-; SIZES: Cold full allocation context 789 with total size 300 is Cold after cloning
+; SIZES: NotCold full allocation context 123 with total size 100 is NotCold after cloning (context id 1)
+; SIZES: Cold full allocation context 456 with total size 200 is Cold after cloning (context id 2)
+; SIZES: Cold full allocation context 789 with total size 300 is Cold after cloning (context id 2)
 
 ; IR: define {{.*}} @main
 ;; The first call to foo does not allocate cold memory. It should call the