[Base Tests] Move base tests to their own subdir

src/xenia/base/premake5.lua

@@ -16,11 +16,4 @@ project("xenia-base")
     "debug_visualizers.natvis",
   })
 
-test_suite("xenia-base-tests", project_root, ".", {
+include("testing")
-  includedirs = {
-    project_root.."/third_party/gflags/src",
-  },
-  links = {
-    "xenia-base",
-  },
-})

src/xenia/base/testing/premake5.lua

@@ -0,0 +1,11 @@
+project_root = "../../../.."
+include(project_root.."/tools/build")
+
+test_suite("xenia-base-tests", project_root, ".", {
+  includedirs = {
+    project_root.."/third_party/gflags/src",
+  },
+  links = {
+    "xenia-base",
+  },
+})