Stop passing --build-tool=ninja in master configs

masters/master.chromium.memory.fyi/master.cfg

Index: masters/master.chromium.memory.fyi/master.cfg
diff --git a/masters/master.chromium.memory.fyi/master.cfg b/masters/master.chromium.memory.fyi/master.cfg
index 8f57a4bc0c42484bcec924f21b9a1c8009413959..d918ab0962bc1c19d1db863386f1689f30a2c6ce 100644
--- a/masters/master.chromium.memory.fyi/master.cfg
+++ b/masters/master.chromium.memory.fyi/master.cfg
@@ -172,7 +172,7 @@ f_chromium_rel_win_drmemory_builder = F_WIN_NINJA(
     # TODO(timurrrr): Might wanna remove chromium_builder_dbg_drmemory_win
     # entirely as ninja supports target lists similar to what we always had
     # on Linux.
-    options=['--build-tool=ninja', '--', 'chromium_builder_dbg_drmemory_win'],
+    options=['chromium_builder_dbg_drmemory_win'],
     factory_properties={
       'gclient_env': {'GYP_DEFINES': ('build_for_tool=drmemory '
                                       'component=shared_library '),
@@ -367,7 +367,7 @@ f_chromium_rel_win_drmemory_64_builder = F_WIN_NINJA(
     target='Release_x64',
     # TODO(bruening): remove "_dbg" from this name in all.gyp as it is
     # not limited to just Debug.
-    options=['--build-tool=ninja', '--', 'chromium_builder_dbg_drmemory_win'],
+    options=['chromium_builder_dbg_drmemory_win'],
     factory_properties={
       'gclient_env': {
         'GYP_DEFINES' : (