Revert "Expose API for resizing image caches"

[jonahwilliams]

Reverts #41415

This is breaking on the web-test shard:

00:06 +11 ~15 -1: /tmp/flutter sdk/packages/flutter/test/painting/image_provider_test.dart: ResizeImage resizes to the correct dimensions                                                              
00:06 +11 ~15 -1: /tmp/flutter sdk/packages/flutter/test/painting/image_provider_test.dart: ResizeImage resizes to the correct dimensions [E]                                                          
  Expected: Size:<Size(14.0, 7.0)>
    Actual: Size:<Size(1.0, 1.0)>
  package:test_api                                   expect$
  package:flutter_test/src/widget_tester.dart 231:3  expect$
  image_provider_test.dart 312:5                     <fn>
  ===== asynchronous gap ===========================
  dart:sdk_internal                                  _async
  image_provider_test.dart 302:57                    <fn>
  ===== asynchronous gap ===========================
  package:stream_channel                             add
  image_provider_test.dart.browser_test.dart 56:17   <fn>

TBR @GaryQian