tests: move the '-hg' postfix for all style tests

We had them on 'test-check-code-hg.t' to avoid collision with the test checking
'check-code' itself. Now that this one have been rename, we can safely remove
this suffix for all of them. This get them in line with 'check-pyflakes.t'.

tests/test-check-code.t

@@ -0,0 +1,15 b''
+#require test-repo
+
+  $ check_code="$TESTDIR"/../contrib/check-code.py
+  $ cd "$TESTDIR"/..
+
+New errors are not allowed. Warnings are strongly discouraged.
+(The writing "no-che?k-code" is for not skipping this file when checking.)
+
+  $ hg locate | sed 's-\\-/-g' |
+  >   xargs "$check_code" --warnings --per-file=0 || false
+  Skipping hgext/zeroconf/Zeroconf.py it has no-che?k-code (glob)
+  Skipping i18n/polib.py it has no-che?k-code (glob)
+  Skipping mercurial/httpclient/__init__.py it has no-che?k-code (glob)
+  Skipping mercurial/httpclient/_readers.py it has no-che?k-code (glob)
+  Skipping mercurial/httpclient/socketutil.py it has no-che?k-code (glob)