Temporarily disable bazel v7 default flips (carbon-language#3495)

Both of these flag flips require work to address. Their default changed
in bazel 7. Note adding these probably breaks versions of bazel older
than 6 -- but an update requirement seems okay in that case, since 6 is
about a year old now.

.bazelrc

@@ -2,6 +2,14 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
+# TODO: Get a better toolchain fix for
+# https://github.com/bazelbuild/bazel/issues/7260
+build --noincompatible_enable_cc_toolchain_resolution
+
+# TODO: https://bazel.build/external/migration for
+# https://github.com/bazelbuild/bazel/issues/18958
+build --noenable_bzlmod
+
 build --crosstool_top=@bazel_cc_toolchain
 build --host_crosstool_top=@bazel_cc_toolchain