Introduce an MSan blacklist and use it to ignore V8.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 98cd460d508a3d1a64a98bae463b0413d344c0a5..7d4a70bd8c75e389694f375998842072ae7b80c4 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -375,6 +375,7 @@
       # MemorySanitizer only works with clang, but msan=1 implies clang=1
       # See http://clang.llvm.org/docs/MemorySanitizer.html
       'msan%': 0,
+      'msan_blacklist%': '<(PRODUCT_DIR)/../../tools/msan/blacklist.txt',
 
       # Use the dynamic libraries instrumented by one of the sanitizers
       # instead of the standard system libraries.
@@ -938,6 +939,7 @@
     'asan_coverage%': '<(asan_coverage)',
     'lsan%': '<(lsan)',
     'msan%': '<(msan)',
+    'msan_blacklist%': '<(msan_blacklist)',
     'tsan%': '<(tsan)',
     'tsan_blacklist%': '<(tsan_blacklist)',
     'use_instrumented_libraries%': '<(use_instrumented_libraries)',
@@ -3525,6 +3527,7 @@
                   '-fsanitize=memory',
                   '-fsanitize-memory-track-origins',
                   '-fPIC',
+                  '-fsanitize-blacklist=<(msan_blacklist)',
                 ],
                 'ldflags': [
                   '-fsanitize=memory',