Suppress new clang warning -Wsizeof-array-div

Disable the clang warning -Wsizeof-array-div with Wno-error to unbreak
the build and see how many instances of the warning there are.

TBR=thakis@

Bug: 1002945
Change-Id: I4539b6cc84bd3a2f1590a5a0ee09b03175942498
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1798890
Commit-Queue: Amy Huang <akhuang@google.com>
Reviewed-by: Reid Kleckner <rnk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695857}

build/config/compiler/BUILD.gn

@@ -1527,10 +1527,19 @@ config("default_warnings") {
           # TODO(https://crbug.com/999886): Clean up, enable.
           "-Wno-final-dtor-non-final-class",
         ]
+
         cflags_c += [
           # TODO(https://crbug.com/995993): Clean up and enable.
           "-Wno-implicit-fallthrough",
         ]
+
+        if (llvm_force_head_revision) {
+          cflags += [
+            # TODO(https://crbug.com/1002945): Evaluate and possibly enable.
+            "-Wno-error=sizeof-array-div",
+          ]
+        }
+
       }
     }
   }