Revert "[build] Prepare switching win asan to 64 bits"

This reverts commit fffa4555.

Reason for revert:
https://build.chromium.org/p/client.v8/builders/V8%20Win32%20ASAN/builds/1905

Original change's description:
> [build] Prepare switching win asan to 64 bits
> 
> This switches the current win32 bots to win32 under the hood in MB. We'll
> remove them and replace them with win64 bots in a follow up on the infra
> side.
> 
> This also infers the clang option from asan, because on windows we need
> to set clang explicitly.
> 
> TBR=sergiyb@chromium.org
> 
> Bug: chromium:786303
> Change-Id: I9dddd5050a21a364c302a761ff15ddd21e97c7dc
> Reviewed-on: https://chromium-review.googlesource.com/883103
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50828}

TBR=machenbach@chromium.org,sergiyb@chromium.org

Change-Id: I2e17aa6ddf44a03d9da29e8b7f7dd2c9f6fe4cb9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:786303
Reviewed-on: https://chromium-review.googlesource.com/883501Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50829}

infra/mb/mb_config.pyl

@@ -74,9 +74,7 @@
       'V8 Win32 - debug builder': 'gn_debug_x86_minimal_symbols',
       'V8 Win32 - nosnap - shared':
         'gn_release_x86_no_snap_shared_minimal_symbols',
-      # TODO(machenbach): Remove after switching to x64 on infra side.
-      'V8 Win32 ASAN': 'gn_release_x64_asan_no_lsan',
-      'V8 Win64 ASAN': 'gn_release_x64_asan_no_lsan',
+      'V8 Win32 ASAN': 'gn_release_x86_asan_no_lsan',
       'V8 Win64': 'gn_release_x64_minimal_symbols',
       'V8 Win64 - debug': 'gn_debug_x64_minimal_symbols',
       'V8 Win64 - msvc': 'gn_release_x64_msvc',
@@ -218,14 +216,13 @@
       'v8_linux64_tsan_concurrent_marking_rel_ng':
           'gn_release_x64_tsan_concurrent_marking_minimal_symbols',
       'v8_linux64_ubsan_rel_ng': 'gn_release_x64_ubsan_vptr_minimal_symbols',
-      # TODO(machenbach): Remove after switching to x64 on infra side.
-      'v8_win_asan_rel_ng': 'gn_release_x64_asan_no_lsan',
+      'v8_win_asan_rel_ng': 'gn_release_x86_asan_no_lsan',
       'v8_win_dbg': 'gn_debug_x86_trybot',
       'v8_win_compile_dbg': 'gn_debug_x86_trybot',
       'v8_win_rel_ng': 'gn_release_x86_trybot',
       'v8_win_nosnap_shared_rel_ng':
         'gn_release_x86_no_snap_shared_minimal_symbols',
-      'v8_win64_asan_rel_ng': 'gn_release_x64_asan_no_lsan',
+      # TODO(machenbach): Rename bot to msvc.
       'v8_win64_msvc_compile_rel': 'gn_release_x64_msvc',
       'v8_win64_dbg': 'gn_debug_x64_minimal_symbols',
       'v8_win64_rel_ng': 'gn_release_x64_trybot',
@@ -493,11 +490,14 @@
     # GN release configs for x86.
     'gn_release_x86': [
       'gn', 'release_bot', 'x86', 'swarming'],
+    'gn_release_x86_asan_no_lsan': [
+      'gn', 'release_bot', 'x86', 'asan', 'clang', 'swarming'],
     'gn_release_x86_asan_no_lsan_verify_heap': [
-      'gn', 'release_bot', 'x86', 'asan', 'swarming', 'v8_verify_heap'],
+      'gn', 'release_bot', 'x86', 'asan', 'clang', 'swarming',
+      'v8_verify_heap'],
     'gn_release_x86_asan_no_lsan_verify_heap_dchecks': [
-      'gn', 'release_bot', 'x86', 'asan', 'swarming', 'dcheck_always_on',
-      'v8_enable_slow_dchecks', 'v8_verify_heap'],
+      'gn', 'release_bot', 'x86', 'asan', 'clang', 'swarming',
+      'dcheck_always_on', 'v8_enable_slow_dchecks', 'v8_verify_heap'],
     'gn_release_x86_disassembler': [
       'gn', 'release_bot', 'x86', 'v8_enable_disassembler'],
     'gn_release_x86_gcc': [
@@ -558,7 +558,7 @@
     },
 
     'asan': {
-      'mixins': ['clang', 'v8_enable_test_features'],
+      'mixins': ['v8_enable_test_features'],
       'gn_args': 'is_asan=true',
       'gyp_defines': 'clang=1 asan=1',
     },