tools: optimize wildcard execution in tools/test.py

Previously for each matching test, it would execute multiple
`node -p` commands to decide the configurations of the executable.
That means if there are 100 tests matched, it will run the Node.js
executable 4*100 times to retrieve the same configurations repeatedly.
This changes the loop order so that it only execute these commands
once and reuse the results for all matching tests.

Author: joyeecheung

tools/test.py

@@ -1712,27 +1712,28 @@ def Main():
   all_unused = [ ]
   unclassified_tests = [ ]
   globally_unused_rules = None
-  for path in paths:
-    for arch in options.arch:
-      for mode in options.mode:
-        vm = context.GetVm(arch, mode)
-        if not exists(vm):
-          print("Can't find shell executable: '%s'" % vm)
-          continue
-        archEngineContext = Execute([vm, "-p", "process.arch"], context)
-        vmArch = archEngineContext.stdout.rstrip()
-        if archEngineContext.exit_code != 0 or vmArch == "undefined":
-          print("Can't determine the arch of: '%s'" % vm)
-          print(archEngineContext.stderr.rstrip())
-          continue
-        env = {
-          'mode': mode,
-          'system': utils.GuessOS(),
-          'arch': vmArch,
-          'type': get_env_type(vm, options.type, context),
-          'asan': get_asan_state(vm, context),
-          'pointer_compression': get_pointer_compression_state(vm, context),
-        }
+
+  for arch in options.arch:
+    for mode in options.mode:
+      vm = context.GetVm(arch, mode)
+      if not exists(vm):
+        print("Can't find shell executable: '%s'" % vm)
+        continue
+      archEngineContext = Execute([vm, "-p", "process.arch"], context)
+      vmArch = archEngineContext.stdout.rstrip()
+      if archEngineContext.exit_code != 0 or vmArch == "undefined":
+        print("Can't determine the arch of: '%s'" % vm)
+        print(archEngineContext.stderr.rstrip())
+        continue
+      env = {
+        'mode': mode,
+        'system': utils.GuessOS(),
+        'arch': vmArch,
+        'type': get_env_type(vm, options.type, context),
+        'asan': get_asan_state(vm, context),
+        'pointer_compression': get_pointer_compression_state(vm, context),
+      }
+      for path in paths:
         test_list = root.ListTests([], path, context, arch, mode)
         unclassified_tests += test_list
         cases, unused_rules = config.ClassifyTests(test_list, env)