Bump clang subrevision to pick up changes in blink-gc-plugin

Blink GC plugin has been updated with a new option
-no-members-in-stack_allocated.

Bug: 1021889
Change-Id: Iacd3e2c9a073c2ebe874734bda76d78cb5422705
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2014964Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735218}

tools/clang/scripts/update.py

@@ -41,7 +41,7 @@ import zipfile
 # Reverting problematic clang rolls is safe, though.
 CLANG_REVISION = 'c2443155a0fb245c8f17f2c1c72b6ea391e86e81'
 CLANG_SVN_REVISION = 'n332890'
-CLANG_SUB_REVISION = 1
+CLANG_SUB_REVISION = 2
 
 PACKAGE_VERSION = '%s-%s-%s' % (CLANG_SVN_REVISION, CLANG_REVISION[:8],
                                 CLANG_SUB_REVISION)