Only use sanitizers with default toolchain on Windows as well.

build/config/sanitizers/sanitizers.gni

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 declare_args() {
   # Compile for Address Sanitizer to find memory bugs.
   is_asan = false
 
   # Compile for Leak Sanitizer to find leaks.
   is_lsan = false
@@ skipping 72 matching lines @@
 
   # Value for -fsanitize-coverage flag. Setting this causes
   # use_sanitizer_coverage to be enabled.
   # Default value when unset and use_afl=true:
   # trace-pc
   # Default value when unset and use_sanitizer_coverage=true:
   #     edge,indirect-calls,8bit-counters
   sanitizer_coverage_flags = ""
 }
 
+# Disable sanitizers for non-default toolchains.
+if (current_toolchain != default_toolchain) {
+  is_asan = false
+  is_cfi = false
+  is_lsan = false
+  is_msan = false
+  is_syzyasan = false
+  is_tsan = false
+  is_ubsan = false
+  is_ubsan_null = false
+  is_ubsan_no_recover = false
+  is_ubsan_security = false
+  is_ubsan_vptr = false
+  msan_track_origins = 0
+  sanitizer_coverage_flags = ""
+  use_cfi_diag = false
+  use_custom_libcxx = false
+  use_drfuzz = false
+  use_libfuzzer = false
+  use_prebuilt_instrumented_libraries = false
+  use_locally_built_instrumented_libraries = false
+  use_sanitizer_coverage = false
+}
+
 # Args that are in turn dependent on other args must be in a separate
 # declare_args block. User overrides are only applied at the end of a
 # declare_args block.
 declare_args() {
   # Use libc++ (buildtools/third_party/libc++ and
   # buildtools/third_party/libc++abi) instead of stdlibc++ as standard library.
   # This is intended to be used for instrumented builds.
   use_custom_libcxx =
       (is_asan && is_linux && !is_chromeos) || is_tsan || is_msan || is_ubsan ||
       is_ubsan_security || use_libfuzzer || use_afl
@@ skipping 39 matching lines @@
 # this condition. We may also be able to find another way to enable your case
 # without having people accidentally get broken builds by compiling an
 # unsupported or unadvisable configurations.
 #
 # For one-off testing, just comment this assertion out.
 assert(!is_debug || !(is_msan || is_ubsan || is_ubsan_null || is_ubsan_vptr),
        "Sanitizers should generally be used in release (set is_debug=false).")
 
 assert(!is_msan || (is_linux && current_cpu == "x64"),
        "MSan currently only works on 64-bit Linux and ChromeOS builds.")