Disable sanitizers for the yasm build tool.

This is only used during building, there's not a good reason to have
the sanitizers enabled since it will significantly slow down the
actual build process and seems to try to allocation nearly a terabyte
of memory at some points.

BUG=861418
TEST=none

Change-Id: I8d2116fbcee6dff2f1ecc422fbca5ef506fad6dd
Reviewed-on: https://chromium-review.googlesource.com/c/1257671Reviewed-by: Evgeniy Stepanov <eugenis@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596035}

third_party/yasm/BUILD.gn

@@ -41,7 +41,11 @@ if (is_debug) {
 
     # Don't define _DEBUG. Modest savings, but good for consistency.
     "//build/config:debug",
+
+    # Don't enable sanitizers for build tools. They slow down the overall build.
+    "//build/config/sanitizers:default_sanitizer_flags",
   ]
+
   configs_to_add += [
     "//build/config:release",
     "//build/config/compiler:optimize_max",