Revert "[gRPC] Suppress CFI cast checks"

This reverts commit 5139af43.

Reason for revert:

Reverting this change in favor of blacklisting CFI cast check in the blacklist
file. See crrev.com/c/1665554

Original change's description:
> [gRPC] Suppress CFI cast checks
>
> ChromeOS builders build Chrome with CFI cast check enabled, so using
> reinterpret_cast on invalid/uninitialized pointer will crash Chrome.
> This is what happened in grpc_core::InlinedVector, which tries to use
> reinterpret_cast before initializing the storage.
>
> While the proper fix should be calling the placement-new operator
> directly on the raw (void*) pointer, the easiest and safest fix for M76
> is just to disable CFI cast checks when building the gRPC library.
>
> I've verified that the crash was reproducible with
> ftl_signaling_strategy if I add `is_cfi=true` (and other required
> arguments) to GN args, and the crash goes away once I've added these
> compiler flag.
>
> Bug: 972108
> Change-Id: Idf874a028af002fafe3a4905d70a3bca71777e42
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1660194
> Commit-Queue: Joe Downing <joedow@chromium.org>
> Reviewed-by: Joe Downing <joedow@chromium.org>
> Auto-Submit: Yuwei Huang <yuweih@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#669203}

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 972108
Change-Id: I9146543b71ab139e4a91bd9add77229c1db9a5c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1665775Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Commit-Queue: Jamie Walch <jamiewalch@chromium.org>
Auto-Submit: Yuwei Huang <yuweih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670275}

third_party/grpc/BUILD.gn

@@ -18,7 +18,6 @@ config("grpc_internal_config") {
   cflags = [
     "-Wno-implicit-fallthrough",
     "-Wno-constant-conversion",
-    "-fno-sanitize=cfi-derived-cast,cfi-unrelated-cast",
   ]
   defines = [ "GRPC_ARES=0" ]
 }