erts: Add etp-lc-dump and etp-ppc-stacktrace macro
kernel: Skip sendfile tests that force async threads

The tests have to be skipped when the emulator running the tests does
not have any async threads.
Merge branch 'lukas/kernel/fix_sendfile_no_async_tests/OTP-11903' into maint

* lukas/kernel/fix_sendfile_no_async_tests/OTP-11903:
  kernel: Skip sendfile tests that force async threads
Merge branch 'lukas/erts/etp-lc-macros/OTP-11904' into maint

* lukas/erts/etp-lc-macros/OTP-11904:
  erts: Add etp-lc-dump and etp-ppc-stacktrace macro
erts: Fix faulty process suspend assert
Merge branch 'lukas/erts/suspend_assert/OTP-11906' into maint

* lukas/erts/suspend_assert/OTP-11906:
  erts: Fix faulty process suspend assert