Meta: Port recent changes to the GN build

e487f70bbf96abe4ff01fcbe4c68b8ae7afbcf8f
f4f4f7781d2a1e5f31632751bf6eb6b1ba833945

Meta/gn/secondary/Userland/Libraries/LibWeb/HTML/Scripting/BUILD.gn

@@ -7,6 +7,8 @@ source_set("Scripting") {
     "Environments.cpp",
     "ExceptionReporter.cpp",
     "Fetching.cpp",
+    "ImportMap.cpp",
+    "ImportMapParseResult.cpp",
     "ModuleMap.cpp",
     "ModuleScript.cpp",
     "Script.cpp",

Meta/gn/secondary/Userland/Libraries/LibWeb/WebIDL/BUILD.gn

@@ -9,5 +9,6 @@ source_set("WebIDL") {
     "ObservableArray.cpp",
     "OverloadResolution.cpp",
     "Promise.cpp",
+    "Tracing.cpp",
   ]
 }