perf(@angular/build): read rendered module length once per module in chunk optimizer (#34045)

* perf(@angular/build): read rendered module length once per module in chunk optimizer

When converting the chunk optimizer output into an esbuild-compatible metafile, the
rendered length of each module was read inside the loop over the module's original
inputs. The `renderedLength` property of a rolldown rendered module is a lazy getter
that transfers the full module code from native memory on every access. Since each
module in this pass is an entire esbuild output chunk, a main chunk of 17 MB with
3,588 inputs resulted in roughly 62 GB of string copies and around 150 seconds spent in
`bundleOutputToEsbuildMetafile`, while the rolldown bundling itself took 3 seconds.

Read the rendered length once per module before iterating its inputs. The generated
metafile is unchanged. On the affected application the `OPTIMIZE_CHUNKS` phase drops
from 179 seconds to 4 seconds and the total production build from 234 to 55 seconds.

Fixes #34044

* Remove performance comments in chunk-optimizer.ts

Removed comments explaining the performance impact of accessing the rendered length in the chunk optimizer.

* Update packages/angular/build/src/builders/application/chunk-optimizer.ts

Co-authored-by: Charles <19598772+clydin@users.noreply.github.com>

---------

Co-authored-by: Charles <19598772+clydin@users.noreply.github.com>

Author: roman-garcia

packages/angular/build/src/builders/application/chunk-optimizer.ts

@@ -113,11 +113,15 @@ function bundleOutputToEsbuildMetafile(
           continue;
         }
 
+        // Read once per module: in Rolldown, `renderedLength` is an uncached getter that
+        // copies the entire module code across the NAPI bridge on each access.
+        const { renderedLength } = renderedModule;
+        
         for (const [originalInputPath, originalInputInfo] of Object.entries(
           originalOutputEntry.inputs,
         )) {
           const proportion = originalInputInfo.bytesInOutput / totalOriginalBytesInModule;
-          const newBytesInOutput = Math.floor(renderedModule.renderedLength * proportion);
+          const newBytesInOutput = Math.floor(renderedLength * proportion);
 
           const existing = newOutputInputs[originalInputPath];
           if (existing) {