Remove --spawn_strategy=standalone and --strategy=Genrule=standalone from bazelrc file

They are no longer needed and will prevent future incompatible migration for RBE build.

Related https://github.com/bazelbuild/bazel/issues/7480

PiperOrigin-RevId: 258244467

.bazelrc

@@ -104,8 +104,6 @@ build:nonccl --define=no_nccl_support=true
 build --define=use_fast_cpp_protos=true
 build --define=allow_oversize_protos=true
 
-build --spawn_strategy=standalone
-build --strategy=Genrule=standalone
 build -c opt
 
 # Make Bazel print out all options from rc files.