Don't reference instrumented-libraryes with sanitizers disabled.

build/config/sanitizers/BUILD.gn

Index: build/config/sanitizers/BUILD.gn
diff --git a/build/config/sanitizers/BUILD.gn b/build/config/sanitizers/BUILD.gn
index 899695127e83fb97e3a87616945266f6b16d267d..319c272f2380e6a363ccf4d523d98c7477fc5472 100644
--- a/build/config/sanitizers/BUILD.gn
+++ b/build/config/sanitizers/BUILD.gn
@@ -8,15 +8,18 @@ import("//build/config/sanitizers/sanitizers.gni")
 # shared_libraries. Unconditionally depend upon this target as it is empty if
 # |is_asan|, |is_lsan|, |is_tsan|, |is_msan| and |use_custom_libcxx| are false.
 group("deps") {
-  deps = [
-    "//third_party/instrumented_libraries:deps",
-  ]
   if (is_asan || is_lsan || is_tsan || is_msan) {
     public_configs = [ ":sanitizer_options_link_helper" ]
-    deps += [ ":options_sources" ]
-  }
-  if (use_custom_libcxx) {
-    deps += [ "//buildtools/third_party/libc++:libcxx_proxy" ]
+    deps = [
+      ":options_sources",
+    ]
+
+    if (use_prebuilt_instrumented_libraries) {
+      deps += [ "//third_party/instrumented_libraries:deps" ]
+    }
+    if (use_custom_libcxx) {
+      deps += [ "//buildtools/third_party/libc++:libcxx_proxy" ]
+    }
   }
 }