Bug 1992103 - Align async modules rejection order with fulfillment order r=jonco

This patch inverts the order in which we reject promises in
AsyncModuleExecutionRejected to match AsyncModuleExecutionFulfilled:
first the promise corresponding to the leaf module (the one that throws)
is rejected, and then its ancestors.

This change was discussed at the July 2025 TC39 meeting.

Spec PR: tc39/ecma262#3695
test262: tc39/test262#4591

Differential Revision: https://phabricator.services.mozilla.com/D267210

UltraBlame original commit: a3cf4d1eef17209c4c4194e07f38fe870c417781

Author: marco-c

js/src/vm/Modules.cpp

@@ -1628,6 +1628,143 @@ moduleObject
 ;
 }
 JS_PUBLIC_API
+JSObject
+*
+JS
+:
+:
+CreateCssModule
+(
+JSContext
+*
+cx
+const
+ReadOnlyCompileOptions
+&
+options
+const
+Value
+&
+cssValue
+)
+{
+Rooted
+<
+ExportNameVector
+>
+exportNames
+(
+cx
+)
+;
+if
+(
+!
+exportNames
+.
+append
+(
+cx
+-
+>
+names
+(
+)
+.
+default_
+)
+)
+{
+ReportOutOfMemory
+(
+cx
+)
+;
+return
+nullptr
+;
+}
+Rooted
+<
+ModuleObject
+*
+>
+moduleObject
+(
+cx
+ModuleObject
+:
+:
+createSynthetic
+(
+cx
+&
+exportNames
+)
+)
+;
+if
+(
+!
+moduleObject
+)
+{
+return
+nullptr
+;
+}
+RootedVector
+<
+Value
+>
+exportValues
+(
+cx
+)
+;
+if
+(
+!
+exportValues
+.
+append
+(
+cssValue
+)
+)
+{
+ReportOutOfMemory
+(
+cx
+)
+;
+return
+nullptr
+;
+}
+if
+(
+!
+ModuleObject
+:
+:
+createSyntheticEnvironment
+(
+cx
+moduleObject
+exportValues
+)
+)
+{
+return
+nullptr
+;
+}
+return
+moduleObject
+;
+}
+JS_PUBLIC_API
 void
 JS
 :
@@ -11283,6 +11420,52 @@ clearAsyncEvaluatingPostOrder
 (
 )
 ;
+if
+(
+module
+-
+>
+hasTopLevelCapability
+(
+)
+)
+{
+MOZ_ASSERT
+(
+module
+-
+>
+getCycleRoot
+(
+)
+=
+=
+module
+)
+;
+if
+(
+!
+ModuleObject
+:
+:
+topLevelCapabilityReject
+(
+cx
+module
+error
+)
+)
+{
+cx
+-
+>
+clearPendingException
+(
+)
+;
+}
+}
 Rooted
 <
 ListObject
@@ -11360,52 +11543,6 @@ error
 )
 ;
 }
-if
-(
-module
--
->
-hasTopLevelCapability
-(
-)
-)
-{
-MOZ_ASSERT
-(
-module
--
->
-getCycleRoot
-(
-)
-=
-=
-module
-)
-;
-if
-(
-!
-ModuleObject
-:
-:
-topLevelCapabilityReject
-(
-cx
-module
-error
-)
-)
-{
-cx
--
->
-clearPendingException
-(
-)
-;
-}
-}
 }
 static
 bool