add C++ tests to bazel

Author: iphydf

auto_tests/BUILD.bazel

@@ -20,7 +20,7 @@ flaky_tests = {
 }
 
 [cc_test(
-    name = src[:-2],
+    name = src[:src.rindex(".")-len(src)],
     size = "small",
     srcs = [src],
     args = ["$(location %s)" % src],
@@ -38,4 +38,4 @@ flaky_tests = {
         "//c-toxcore/toxcore:DHT_srcs",
         "//c-toxcore/toxencryptsave",
     ],
-) for src in glob(["*_test.c"])]
+) for src in glob(["*_test.c*"])]