Make sure the '--append_flaky_log' flag is set on all test.py calls except for the first one

tools/bots/compiler.py

Index: tools/bots/compiler.py
diff --git a/tools/bots/compiler.py b/tools/bots/compiler.py
index e378b4d66f5281110c394f53c88c50fc732b44d4..9e88f2c140303d03f0b9cbcf5de7e0d5e3560195 100644
--- a/tools/bots/compiler.py
+++ b/tools/bots/compiler.py
@@ -99,7 +99,7 @@ def TestStepName(name, flags):
   flags = [x for x in flags if not '=' in x]
   return ('%s tests %s' % (name, ' '.join(flags))).strip()
 
-
+IsFirstTestStepCall = True
 def TestStep(name, mode, system, compiler, runtime, targets, flags):
   step_name = TestStepName(name, flags)
   with bot.BuildStep(step_name, swallow_error=True):
@@ -130,6 +130,12 @@ def TestStep(name, mode, system, compiler, runtime, targets, flags):
     else:
       cmd.extend(['--progress=buildbot', '-v'])
 
+    global IsFirstTestStepCall
+    if IsFirstTestStepCall:
+      IsFirstTestStepCall = False
+    else:
+      cmd.append('--append_flaky_log')
+
     if flags:
       cmd.extend(flags)
     cmd.extend(targets)