Merge branch 'jc/test-i18ngrep'

Another step to deprecate test_i18ngrep.

* jc/test-i18ngrep:
  tests: teach callers of test_i18ngrep to use test_grep
  test framework: further deprecate test_i18ngrep

t/t2004-checkout-cache-temp.sh

@@ -93,7 +93,7 @@ test_expect_success 'checkout all stages of unknown path' '
 	rm -f path* .merge_* actual &&
 	test_must_fail git checkout-index --stage=all --temp \
 		-- does-not-exist 2>stderr &&
-	test_i18ngrep not.in.the.cache stderr
+	test_grep not.in.the.cache stderr
 '
 
 test_expect_success 'checkout all stages/one file to nothing' '