[gn] Provide explicit name in component builds

With https://crrev.com/c/4166369 the default names changed from
e.g. libv8.so to lib_v8.so.
This causes at least some issues on build bots but might also
impact other projects assuming certain names in case of component
builds.
The default naming can be prevented by providing an explicit
{output_name} on each component.

No-Tree-Checks: true
Change-Id: I501c3f6c530e6d3896e2303ee75a0c4a4d07dfca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4194732
Reviewed-by: Lutz Vahl <vahl@chromium.org>
Auto-Submit: Matthias Liedtke <mliedtke@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85483}

gni/v8.gni

@@ -302,6 +302,7 @@ template("v8_executable") {
 
 template("v8_component") {
   component(target_name) {
+    output_name = target_name
     forward_variables_from(invoker,
                            "*",
                            [