[LNT] Python 3 support: stable showtests output

lnt showtests output depends on the iteration order of a set, which has
no guarantee whatsoever. This makes the result of test
tests/lnttool/showtests.shtest unstable in particular accross Python 2
and 3. This commit makes the lnt.tests constructor return a new sorted
list instead of the set, thus guaranteeing a stable output of lnt
showtests. It also lists tests in alphabetical order which makes it
nicer for users.

Reviewers: cmatthews, hubert.reinterpretcast, kristof.beyls

Reviewed By: cmatthews

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D68220

llvm-svn: 374305

Author: Thomas Preud'homme

lnt/tests/__init__.py

@@ -12,7 +12,7 @@ def get_names():
 
     Return the list of known built-in test names.
     """
-    return _known_tests
+    return sorted(_known_tests)
 
 
 def get_module(name):

tests/lnttool/showtests.shtest

@@ -1,5 +1,5 @@
 # RUN: lnt showtests | FileCheck %s
 # CHECK: Available tests:
 # CHECK-NEXT: compile    - Single file compile-time performance testing
-# CHECK-NEXT: test_suite - LLVM test-suite
 # CHECK-NEXT: nt         - LLVM test-suite compile and execution tests
+# CHECK-NEXT: test_suite - LLVM test-suite