LibWeb: Fulfill TransformStream promises with the correct "reason"

We need to use the reason provided to the abort algorithm, not the one
from the resolved cancel promise (which will be undefined).

Libraries/LibWeb/Streams/AbstractOperations.cpp

@@ -5438,7 +5438,7 @@ GC::Ref<WebIDL::Promise> transform_stream_default_sink_abort_algorithm(Transform
     // 7. React to cancelPromise:
     WebIDL::react_to_promise(cancel_promise,
         // 1. If cancelPromise was fulfilled, then:
-        GC::create_function(realm.heap(), [&realm, readable, controller](JS::Value reason) -> WebIDL::ExceptionOr<JS::Value> {
+        GC::create_function(realm.heap(), [&realm, readable, controller, reason](JS::Value) -> WebIDL::ExceptionOr<JS::Value> {
             // 1. If readable.[[state]] is "errored", reject controller.[[finishPromise]] with readable.[[storedError]].
             if (readable->state() == ReadableStream::State::Errored) {
                 WebIDL::reject_promise(realm, *controller->finish_promise(), readable->stored_error());

Tests/LibWeb/Text/expected/wpt-import/streams/transform-streams/errors.any.txt

@@ -2,8 +2,7 @@ Harness status: OK
 
 Found 21 tests
 
-19 Pass
-2 Fail
+21 Pass
 Pass	TransformStream errors thrown in transform put the writable and readable in an errored state
 Pass	TransformStream errors thrown in flush put the writable and readable in an errored state
 Pass	errored TransformStream should not enqueue new chunks
@@ -23,5 +22,5 @@ Pass	controller.error() should do nothing after readable.cancel() resolves
 Pass	controller.error() should do nothing after writable.abort() has completed
 Pass	controller.error() should do nothing after a transformer method has thrown an exception
 Pass	erroring during write with backpressure should result in the write failing
-Fail	a write() that was waiting for backpressure should reject if the writable is aborted
-Fail	the readable should be errored with the reason passed to the writable abort() method
+Pass	a write() that was waiting for backpressure should reject if the writable is aborted
+Pass	the readable should be errored with the reason passed to the writable abort() method

Tests/LibWeb/Text/expected/wpt-import/streams/transform-streams/reentrant-strategies.any.txt

@@ -2,8 +2,7 @@ Harness status: OK
 
 Found 11 tests
 
-10 Pass
-1 Fail
+11 Pass
 Pass	enqueue() inside size() should work
 Pass	terminate() inside size() should work
 Pass	error() inside size() should work
@@ -14,4 +13,4 @@ Pass	read() inside of size() should work
 Pass	writer.write() inside size() should work
 Pass	synchronous writer.write() inside size() should work
 Pass	writer.close() inside size() should work
-Fail	writer.abort() inside size() should work
+Pass	writer.abort() inside size() should work