feat(compiler-cli): no longer re-export external symbols by default (#28633)

With #28594 we refactored the `@angular/compiler` slightly to
allow opting out from external symbol re-exports which are
enabled by default.

Since symbol re-exports only benefit projects which have a
very strict dependency enforcement, external symbols should
not be re-exported by default as this could grow the size of
factory files and cause unexpected behavior with Angular's
AOT symbol resolving (e.g. see: #25644).

Note that the common strict dependency enforcement for source
files does still work with external symbol re-exports disabled,
but there are also strict dependency checks that enforce strict
module dependencies also for _generated files_ (such as the
ngfactory files). This is how Google3 manages it's dependencies
and therefore external symbol re-exports need to be enabled within
Google3.

Also "ngtsc" also does not provide any way of using external symbol
re-exports, so this means that with this change, NGC can partially
match the behavior of "ngtsc" then (unless explicitly opted-out).

As mentioned before, internally at Google symbol re-exports need to
be still enabled, so the `ng_module` Bazel rule will enable the symbol
re-exports by default when running within Blaze.

Fixes #25644.

PR Close #28633

packages/compiler/src/aot/summary_serializer.ts

@@ -23,7 +23,7 @@ export function serializeSummaries(
           CompileTypeMetadata
     }[],
     createExternalSymbolReexports =
-        true): {json: string, exportAs: {symbol: StaticSymbol, exportAs: string}[]} {
+        false): {json: string, exportAs: {symbol: StaticSymbol, exportAs: string}[]} {
   const toJsonSerializer = new ToJsonSerializer(symbolResolver, summaryResolver, srcFileName);
 
   // for symbols, we use everything except for the class metadata itself