Disable frame pointer omission for Windows ARM64 debug build

RtlCaptureStackBackTrace on Windows ARM64 relies on frame pointer chain to walk
the stack which is guaranteed by "/Oy-" option for clang-cl.exe/cl.exe. This
option is enabled in optimized build but not in debug build which could cause
missing Chromium modules in stack trace.

Bug: 893460
Change-Id: I60c3196aa8917209cfcf059eecc1660c291f5c17
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1854825Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Tom Tan <Tom.Tan@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#705184}

build/config/compiler/BUILD.gn

@@ -2039,6 +2039,12 @@ config("no_optimize") {
       "/Ob0",  # Disable all inlining (on by default).
       "/GF",  # Enable string pooling (off by default).
     ]
+
+    if (target_cpu == "arm64") {
+      # Disable omitting frame pointers for no_optimize build because stack
+      # trace on Windows ARM64 relies on it.
+      cflags += [ "/Oy-" ]
+    }
   } else if (is_android && !android_full_debug) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.