Change clang subrevision to reflect changes in blink-gc-plugin

Blink GC plugin has been updated with a new option -no-gc-finalized.

Bug: 990913
Change-Id: I8bc320162e936bb85be9e53e2beaec63163768ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1798609Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696027}

tools/clang/scripts/update.py

@@ -39,7 +39,7 @@ import zipfile
 # Reverting problematic clang rolls is safe, though.
 CLANG_REVISION = '8455294f2ac13d587b13d728038a9bffa7185f2b'
 CLANG_SVN_REVISION = '371202'
-CLANG_SUB_REVISION = 1
+CLANG_SUB_REVISION = 2
 
 PACKAGE_VERSION = '%s-%s-%s' % (CLANG_SVN_REVISION, CLANG_REVISION[:8],
                                 CLANG_SUB_REVISION)