Add -DDEBUG and -O0 for dbg compiles (#556)

In the past for Objective-C these came from
incompatible_avoid_hardcoded_objc_compilation_flags, which was flipped
in bazel 9.x. We pass these 2 for fastbuild as well.

Author: keith

crosstool/cc_toolchain_config.bzl

@@ -1638,7 +1638,7 @@ please file an issue at https://github.com/bazelbuild/apple_support/issues/new
                     ACTION_NAMES.objc_compile,
                     ACTION_NAMES.objcpp_compile,
                 ],
-                flag_groups = [flag_group(flags = ["-g"])],
+                flag_groups = [flag_group(flags = ["-O0", "-DDEBUG", "-g"])],
                 with_features = [with_feature_set(features = ["dbg"])],
             ),
         ],

test/compiling_tests.bzl

@@ -378,13 +378,13 @@ def compiling_test_suite(name):
         expected_argv = [
             "-D_FORTIFY_SOURCE=1",
             "-fstack-protector",
+            "-O0",
+            "-DDEBUG",
             "-g",
         ],
         not_expected_argv = [
-            "-DDEBUG",
             "-DNDEBUG",
             "-g0",
-            "-O0",
             "-O2",
         ],
         mnemonic = "CppCompile",