[release-branch.go1.26] Disable innerloop network isolation

[dagood]

• https://github.com/microsoft/go-lab/issues/206

Apply this to 1.26 branch as well:

• [release-branch.go1.25] Disable innerloop network isolation #2115

[dagood]

microsoft-go (linux-amd64 nocgo (ubuntu) [systemcrypto,ms_nocgo_opensslcrypto], probably flaky:

=== RUN   TestGdbBacktrace
=== PAUSE TestGdbBacktrace
=== CONT  TestGdbBacktrace
    runtime-gdb_test.go:82: gdb version 12.1
    runtime-gdb_test.go:524: GDB command timed out after 6m46.007064048s: /usr/bin/gdb -nx -batch -iex add-auto-load-safe-path /__w/1/s/go/src/runtime -ex set startup-with-shell off -ex break main.eee -ex run -ex backtrace -ex continue /tmp/TestGdbBacktrace934638479/001/a.exe
    runtime-gdb_test.go:529: gdb output:
        Loading Go Runtime support.
        Breakpoint 1 at 0x488f40: file /tmp/TestGdbBacktrace934638479/001/main.go, line 17.
        warning: Error disabling address space randomization: Operation not permitted
        [New LWP 63483]
        [New LWP 63484]
        [New LWP 63485]
        [New LWP 63486]
        
        Thread 1 "a.exe" hit Breakpoint 1, main.eee (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:17
        17	func eee() bool { return true }
        #0  main.eee (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:17
        #1  0x0000000000488f36 in main.ddd (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:14
        #2  0x0000000000488f0f in main.ccc (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:11
        #3  0x0000000000488eef in main.bbb (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:8
        #4  0x0000000000488ecf in main.aaa (~r0=<optimized out>) at /tmp/TestGdbBacktrace934638479/001/main.go:5
        #5  0x0000000000488f6f in main.main () at /tmp/TestGdbBacktrace934638479/001/main.go:22
        [LWP 63484 exited]
        [LWP 63483 exited]
        [LWP 63475 exited]
        [LWP 63486 exited]
    runtime-gdb_test.go:549: gdb exited with error: signal: killed
--- FAIL: TestGdbBacktrace (406.69s)