Build clang without static analyzer and arc migrator.

Makes clang package ~7% smaller and lets the tot and upload bots
cycle ~7% faster. Since we don't use either of these features,
let's disable them.

Bug: 925145
Change-Id: I2570531caca6ca38173da35b8d4a76a925b31044
Reviewed-on: https://chromium-review.googlesource.com/c/1437255Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626285}

tools/clang/scripts/update.py

@@ -35,7 +35,7 @@ if use_head_revision:
   CLANG_REVISION = 'HEAD'
 
 # This is incremented when pushing a new build of Clang at the same revision.
-CLANG_SUB_REVISION=1
+CLANG_SUB_REVISION=2
 
 PACKAGE_VERSION = "%s-%s" % (CLANG_REVISION, CLANG_SUB_REVISION)
 
@@ -535,6 +535,8 @@ def UpdateClang(args):
                      # Statically link MSVCRT to avoid DLL dependencies.
                      '-DLLVM_USE_CRT_RELEASE=MT',
                      '-DCLANG_PLUGIN_SUPPORT=OFF',
+                     '-DCLANG_ENABLE_STATIC_ANALYZER=OFF',
+                     '-DCLANG_ENABLE_ARCMT=OFF',
                      ]
 
   if sys.platform != 'win32':