Revert "Use Kernel frontend from run_vm_tests."

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
diff --git a/runtime/include/dart_api.h b/runtime/include/dart_api.h
index 02ec3bdef95f15282f8cace177ee6e68bd336e84..4a034a24ca76235bc57b87c2ed89d69a3ef0df61 100644
--- a/runtime/include/dart_api.h
+++ b/runtime/include/dart_api.h
@@ -3155,15 +3155,6 @@ DART_EXPORT Dart_Port Dart_KernelPort();
 DART_EXPORT Dart_KernelCompilationResult
 Dart_CompileToKernel(const char* script_uri);
 
-typedef struct {
-  const char* uri;
-  const char* source;
-} Dart_SourceFile;
-DART_EXPORT Dart_KernelCompilationResult
-Dart_CompileSourcesToKernel(const char* script_uri,
-                            int source_files_count,
-                            Dart_SourceFile source_files[]);
-
 #define DART_KERNEL_ISOLATE_NAME "kernel-service"
 
 /*