Roll clang and switch to fsanitize=fuzzer-no-link

A bit of build file reshuffling to support standalone fuzzer targets.
See discussion in https://chromium-review.googlesource.com/c/chromium/src/+/1244802

TBR: fmayer
Test: built with "is_debug=false use_libfuzzer=true is_asan=true" and ran fuzzers
Change-Id: Ic64185eedd8b58c59569230c22a5ec880ebdb0b4
diff --git a/.travis.yml b/.travis.yml
index 9d3ab45..fcb7192 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -122,6 +122,7 @@
     - buildtools/linenoise
     - buildtools/libcxx
     - buildtools/libcxxabi
+    - buildtools/libfuzzer
     - buildtools/libunwind
 
 before_install: