Update prebuilt Clang to r353983c.

clang 9.0.3 (based on r353983c) from build 5484270.

Bug: http://b/129712936
Test: N/A
Change-Id: I005771b46092a05f09dfbb5d16bba73942f8d0a6
Merged-In: I37cb4adfbca3843b2696cba4d2cd3d480c47a20b
(cherry picked from commit 617afa429abdb5927186e2ecdf495ee4f3e943f1)
2394 files changed