Fine. Extract LibraryRequirements to group per-library data

The `RequirementsManifest` class previously managed several distinct
maps keyed by library URI to track top-level elements, instances,
interfaces, and extensions. This change introduces a new
`LibraryRequirements` class to encapsulate all requirements for a single
library.

This refactoring simplifies the structure of `RequirementsManifest` by
replacing four separate maps with a single map from a library's URI to
its `LibraryRequirements` object. This improves data locality and makes
the code easier to follow.

As part of this change, several fields were also renamed for clarity:
- `requestedFields` is now `requestedDeclaredFields` (and similar for
  getters, setters, and methods).
- `allDeclaredConstructors` is now `allConstructors`.

Some printed requirements are now empty because we usually exclude SDK
libraries.

Change-Id: I3a64a9e890fa6155d16b08b255d80b8d0a937c8e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445346
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -109,7 +109,7 @@ testFineAfterLibraryAnalyzerHook;
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 520;
+  static const int DATA_VERSION = 521;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/fine/library_manifest.dart

@@ -110,9 +110,9 @@ class LibraryManifest {
     ]);
   }
 
-  /// Returns the ID of a top-level element either declared or re-exported,
-  /// or `null` if there is no such element.
-  ManifestItemId? getExportedId(LookupName name) {
+  /// Returns the ID of a declared top-level element, or `null` if there is no
+  /// such element.
+  ManifestItemId? getDeclaredId(LookupName name) {
     return declaredClasses[name]?.id ??
         declaredEnums[name]?.id ??
         declaredExtensions[name]?.id ??
@@ -121,8 +121,13 @@ class LibraryManifest {
         declaredTypeAliases[name]?.id ??
         declaredGetters[name]?.id ??
         declaredSetters[name]?.id ??
-        declaredFunctions[name]?.id ??
-        reExportMap[name];
+        declaredFunctions[name]?.id;
+  }
+
+  /// Returns the ID of a top-level element either declared or re-exported,
+  /// or `null` if there is no such element.
+  ManifestItemId? getExportedId(LookupName name) {
+    return getDeclaredId(name) ?? reExportMap[name];
   }
 
   void write(BufferedSink sink) {