Fix a windows build issue

runtime/vm/simulator_arm64.cc

Index: runtime/vm/simulator_arm64.cc
===================================================================
--- runtime/vm/simulator_arm64.cc	(revision 43665)
+++ runtime/vm/simulator_arm64.cc	(working copy)
@@ -198,9 +198,9 @@
     *value = sim_->get_pc();
     return true;
   }
-  bool retval = SScanF(desc, "0x%"Px64, value) == 1;
+  bool retval = SScanF(desc, "0x%" Px64, value) == 1;
   if (!retval) {
-    retval = SScanF(desc, "%"Px64, value) == 1;
+    retval = SScanF(desc, "%" Px64, value) == 1;
   }
   return retval;
 }
@@ -479,9 +479,9 @@
           uint64_t value;
           if (strcmp(arg1, "icount") == 0) {
             value = sim_->get_icount();
-            OS::Print("icount: %"Pu64" 0x%"Px64"\n", value, value);
+            OS::Print("icount: %" Pu64 " 0x%" Px64 "\n", value, value);
           } else if (GetValue(arg1, &value)) {
-            OS::Print("%s: %"Pu64" 0x%"Px64"\n", arg1, value, value);
+            OS::Print("%s: %" Pu64 " 0x%" Px64 "\n", arg1, value, value);
           } else {
             OS::Print("%s unrecognized\n", arg1);
           }
@@ -508,7 +508,7 @@
           uint64_t long_value;
           if (GetDValue(arg1, &long_value)) {
             double dvalue = bit_cast<double, uint64_t>(long_value);
-            OS::Print("%s: %"Pu64" 0x%"Px64" %.8g\n",
+            OS::Print("%s: %" Pu64 " 0x%" Px64 " %.8g\n",
                 arg1, long_value, long_value, dvalue);
           } else {
             OS::Print("%s unrecognized\n", arg1);
@@ -533,8 +533,8 @@
             const float sval1 = bit_cast<float, int32_t>(s1);
             const float sval2 = bit_cast<float, int32_t>(s2);
             const float sval3 = bit_cast<float, int32_t>(s3);
-            OS::Print("%s: %"Pu64" 0x%"Px64" %.8g\n", arg1, d0, d0, dval0);
-            OS::Print("%s: %"Pu64" 0x%"Px64" %.8g\n", arg1, d1, d1, dval1);
+            OS::Print("%s: %" Pu64 " 0x%" Px64 " %.8g\n", arg1, d0, d0, dval0);
+            OS::Print("%s: %" Pu64 " 0x%" Px64 " %.8g\n", arg1, d1, d1, dval1);
             OS::Print("%s: %d 0x%x %.8g\n", arg1, s0, s0, sval0);
             OS::Print("%s: %d 0x%x %.8g\n", arg1, s1, s1, sval1);
             OS::Print("%s: %d 0x%x %.8g\n", arg1, s2, s2, sval2);
@@ -560,7 +560,7 @@
               obj.Print();
 #endif  // defined(DEBUG)
             } else {
-              OS::Print("0x%"Px64" is not an object reference\n", value);
+              OS::Print("0x%" Px64 " is not an object reference\n", value);
             }
           } else {
             OS::Print("%s unrecognized\n", arg1);
@@ -579,7 +579,7 @@
             // No length parameter passed, assume 10 instructions.
             if (Simulator::IsIllegalAddress(start)) {
               // If start isn't a valid address, warn and use PC instead.
-              OS::Print("First argument yields invalid address: 0x%"Px64"\n",
+              OS::Print("First argument yields invalid address: 0x%" Px64 "\n",
                         start);
               OS::Print("Using PC instead\n");
               start = sim_->get_pc();
@@ -591,7 +591,7 @@
           if (GetValue(arg1, &start) && GetValue(arg2, &length)) {
             if (Simulator::IsIllegalAddress(start)) {
               // If start isn't a valid address, warn and use PC instead.
-              OS::Print("First argument yields invalid address: 0x%"Px64"\n",
+              OS::Print("First argument yields invalid address: 0x%" Px64 "\n",
                         start);
               OS::Print("Using PC instead\n");
               start = sim_->get_pc();
@@ -3303,7 +3303,7 @@
 void Simulator::InstructionDecode(Instr* instr) {
   pc_modified_ = false;
   if (IsTracingExecution()) {
-    OS::Print("%"Pu64, icount_);
+    OS::Print("%" Pu64, icount_);
     const uword start = reinterpret_cast<uword>(instr);
     const uword end = start + Instr::kInstrSize;
     Disassembler::Disassemble(start, end);