message: Remove Win32 ASan from mb config.
  Cr-Commit-Position: refs/heads/master@{#28120}
diff: 'Win32 Builder (Clang)': 'win_clang_pure_release_bot_x86',
  'Win64 Debug (Clang)': 'win_clang_debug_bot_x64',
  'Win64 Release (Clang)': 'win_clang_release_bot_x64',
  - 'Win32 ASan': 'win_asan_clang_release_bot_x86',
  'Win64 ASan': 'win_asan_clang_release_bot_x64',
  'Win64 UWP': 'win_uwp_release_bot_x64',
  'Win (more configs)': {
  'win_msvc_release_bot_x64': [
  'no_clang', 'release_bot', 'x64', 'no_lld',
  ],
  - 'win_asan_clang_release_bot_x86': [
  - 'asan', 'clang', 'full_symbols', 'openh264', 'release_bot', 'x86',
  - 'win_fastlink',
  - ],
  'win_asan_clang_release_bot_x64': [
  'asan', 'clang', 'full_symbols', 'openh264', 'release_bot', 'x64',
  'win_fastlink',
  