Update aosp/master Clang for rebase to r275480

Bug: http://b/31320715

This merges commit ac9cc4764cf47a6c3f031687d8592e080c9f5001 from
aosp/dev.

Test: Build AOSP and run RenderScript tests (host tests for slang and
libbcc, RsTest, CTS)

Change-Id: Ic2875e5c3673c83448cd7d1013861e42947b1b55
diff --git a/.gitignore b/.gitignore
index 3d07e81..fc84248 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,3 +33,5 @@
 # Sphinx build products
 docs/_build
 docs/analyzer/_build
+# debug info testsuite
+test/debuginfo-tests