Update bazelrc preset --nolegacy_external_runfiles for Bazel 8

[hofbi]

The performance.bazelrc preset defines

bazel-lib/.aspect/bazelrc/performance.bazelrc

Line 14 in d042d56

build --nolegacy_external_runfiles

. In Bazel 8 --legacy_external_runfiles (bazelbuild/bazel#23574; now defaults to false).

Should we move the definition from performance.bazelrc into the Bazel 6 and Bazel 7 rc files? This would result in a small duplication.

[alexeagle]

Yes please, moving to bazel6 and bazel7 is the right solution. I don't think we want to create a bazel_6_or_7 file, the duplication is not worth the complexity.