tests: add a test demonstrate that 'revert -i' ignores nonexistent patterns

As described in issue5789, when revert is called through:

  hg revert -i <some file that does not exist>

we'd expect the command to abort early. Currently, it just warns about
missing file but prompt about files unrelated to user arguments.

tests/test-revert-interactive.t

@@ -420,4 +420,17 b' When a line without EOL is selected duri'
   $ cat a
   0
 
+When specified pattern does not exist, we should exit early (issue5789).
+
+  $ hg files
+  a
+  $ hg rev b
+  b: no such file in rev b40d1912accf
+  $ hg rev -i b
+  b: no such file in rev b40d1912accf
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] abort: response expected
+  [255]
+
   $ cd ..