[Fuchsia] Fix Platform.executable and Platform.resolvedExecutable

runtime/bin/platform_win.cc

Index: runtime/bin/platform_win.cc
diff --git a/runtime/bin/platform_win.cc b/runtime/bin/platform_win.cc
index af3845595c1e902fdbaeffd79fb2ec72c397b2bd..a15f437391174e0838f4595f80705c8920b9c21a 100644
--- a/runtime/bin/platform_win.cc
+++ b/runtime/bin/platform_win.cc
@@ -259,6 +259,11 @@ char** Platform::Environment(intptr_t* count) {
 }
 
 
+const char* Platform::GetExecutableName() {
+  return executable_name_;
+}
+
+
 const char* Platform::ResolveExecutablePath() {
   // GetModuleFileNameW cannot directly provide information on the
   // required buffer size, so start out with a buffer large enough to