tests/test-diff-issue2761.t

tests: use NO_CHECK_EOF for fragments used to test importing via extension

test-extension.t is excluded in test-check-module-imports.t, because
import-checker.py reports that some python code fragments in it does
not import modules in recommended style.

These code fragments are used to test importing modules relatively and
absolutely via extension (e.g. issue4029, issue5208, and so on). Test
specific package hierarchy becomes complicated for this purpose, and
it seems reasonable to avoid checking these code fragments with
import-checker.py.

But on the other hand, other code fragments in test-extension.t should
be checked by import-checker.py.

Therefore, this patch uses NO_CHECK_EOF limit mark only for python
code fragments, which are used to test importing via extension in
test-extension.t. NO_CHECK_EOF limit mark tells import-checker.py that
this code fragment should be ignored, via testparseutil.py.

Test issue2761

  $ hg init

  $ touch to-be-deleted
  $ hg add
  adding to-be-deleted
  $ hg ci -m first
  $ echo a > to-be-deleted
  $ hg ci -m second
  $ rm to-be-deleted
  $ hg diff -r 0

Same issue, different code path

  $ hg up -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ touch does-not-exist-in-1
  $ hg add
  adding does-not-exist-in-1
  $ hg ci -m third
  $ rm does-not-exist-in-1
  $ hg diff -r 1