Update the default GYP flags for sanitizer tools.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 73c2a4461b33f77cf44c58132bf493612feb57a7..abc3253a50ed7dd314822c4f93855b9c81e4dda4 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -2030,7 +2030,7 @@
         ],
       }],
 
-      ['asan==1', {
+      ['asan==1 or msan==1 or lsan==1 or tsan==1', {
         'clang%': 1,
         'use_allocator%': 'none',
       }],
@@ -2042,15 +2042,14 @@
         # runtime is fully adopted. See http://crbug.com/242503.
         'mac_strip_release': 0,
       }],
-      ['lsan==1', {
-        'clang%': 1,
-      }],
       ['tsan==1', {
-        'clang%': 1,
         'use_custom_libcxx%': 1,
       }],
       ['msan==1', {
-        'clang%': 1,
+        'use_custom_libcxx%': 1,
+        # Running the V8-generated code on an ARM simulator is a powerful hack
+        # that allows the tool to see the memory accesses from JITted code.

[Alexander Potapenko, 2014/06/16 10:40:43]

Is this required to avoid false positives? If so, please mention that.

+        'v8_target_arch': 'arm64',
       }],
 
       ['OS=="linux" and clang_type_profiler==1', {