Fix windows GN build

Fix the reference to the sanitizers to not be needed on windows,
and remove a stray reference to a file that doesn't exist any more.

TBR=brettw@chromium.org, scottmg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/694263004

Cr-Commit-Position: refs/heads/master@{#302677}

build/config/compiler/BUILD.gn

@@ -46,7 +46,9 @@ config("default_include_dirs") {
 }
 
 # TODO(GYP): is_ubsan, is_ubsan_vptr
-using_sanitizer = is_asan || is_lsan || is_tsan || is_msan
+if (!is_win) {
+  using_sanitizer = is_asan || is_lsan || is_tsan || is_msan
+}
 
 # compiler ---------------------------------------------------------------------
 #

net/BUILD.gn

@@ -289,7 +289,6 @@ component("net") {
     }
     if (is_win) {
       sources -= [
-        "cert/cert/sha256_legacy_support_openssl_win.cc",
         "ssl/openssl_platform_key_win.cc",
       ]
     }