Revert "Turn the VM's dart:typed_data into a patch"

tools/patch_sdk.dart

Index: tools/patch_sdk.dart
diff --git a/tools/patch_sdk.dart b/tools/patch_sdk.dart
index e9980eab858fc52d212d1ab8e4b1b2710547f4fc..5a76ff5f5d368504b90eab6e991d5bf89294a893 100644
--- a/tools/patch_sdk.dart
+++ b/tools/patch_sdk.dart
@@ -110,7 +110,14 @@ void main(List<String> argv) {
 
     var libraryOut = path.join(sdkLibIn, library.path);
     var libraryIn;
-    if (mode == 'ddc' && library.path.contains(INTERNAL_PATH)) {
+    if (mode == 'vm' && library.path.contains('typed_data.dart')) {
+      // dart:typed_data is unlike the other libraries in the SDK. The VM does
+      // not apply a patch to the base SDK implementation of the library.
+      // Instead, the VM provides a replacement implementation and ignores the
+      // sources in the SDK.
+      libraryIn =
+          path.join(dartDir, 'runtime', 'lib', 'typed_data.dart');
+    } else if (mode == 'ddc' && library.path.contains(INTERNAL_PATH)) {
       libraryIn =
           path.join(privateIn, library.path.replaceAll(INTERNAL_PATH, ''));
     } else {