Disable Wimplicit-int-float-conversion on the clang tot bots in nocompile tests as well.

TBR=hans

Bug: 989932
Change-Id: Id91684d103ad0ce6970c8b69d530d6faf84fc6af
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731429Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683177}

build/nocompile.gni

@@ -56,6 +56,7 @@
 # least processed when things go right.
 
 import("//build/config/clang/clang.gni")
+import("//build/toolchain/toolchain.gni")
 import("//testing/test.gni")
 
 declare_args() {
@@ -101,6 +102,10 @@ if (enable_nocompile_tests) {
         "-I" + rebase_path("//", root_build_dir),
         "-I" + rebase_path(root_gen_dir, root_build_dir),
       ]
+      if (llvm_force_head_revision) {
+        # TODO(https://crbug.com/989932): Track build/config/compiler/BUILD.gn
+        args += [ "-Wno-implicit-int-float-conversion" ]
+      }
       if (sysroot != "") {
         args += [
           "--sysroot",