Roll Clang on Windows to r201742 to fix more net_unittests etc.

BUG=none
TBR=rnk@chromium.org

Review URL: https://codereview.chromium.org/171423010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252132 0039d316-1c4b-4281-b951-d872f2087c98

tools/clang/scripts/update.py

@@ -15,7 +15,7 @@ import sys
 # https://code.google.com/p/chromium/wiki/UpdatingClang
 # Reverting problematic clang rolls is safe, though.
 # Note: this revision is only used for Windows. Other platforms use update.sh.
-LLVM_WINDOWS_REVISION = '201612'
+LLVM_WINDOWS_REVISION = '201742'
 
 # Path constants. (All of these should be absolute paths.)
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))