Temporary workaround to make VM bots greener.

The reason are data races at isolate creation/shutdown. Further investigation
to fix the root cause needed.

TBR=johnmccutchan@google.com,

BUG=

Review URL: https://codereview.chromium.org/1531763002 .

runtime/bin/isolate_data.h

@@ -36,12 +36,14 @@ class IsolateData {
       this->packages_file = strdup(packages_file);
     }
   }
+#if 0
   ~IsolateData() {
     free(script_url);
     free(package_root);
     free(packages_file);
     free(udp_receive_buffer);
   }
+#endif
 
   char* script_url;
   char* package_root;

runtime/vm/dart_api_impl.cc

@@ -77,6 +77,7 @@ const char* CanonicalFunction(const char* func) {
   }
 }
 
+#if 0
 #define API_TIMELINE_DURATION                                                  \
   TimelineDurationScope tds(Thread::Current(),                                 \
                             Timeline::GetVMApiStream(),                        \
@@ -86,6 +87,10 @@ const char* CanonicalFunction(const char* func) {
   TimelineBeginEndScope tbes(Thread::Current(),                                \
                              Timeline::GetVMApiStream(),                       \
                              CURRENT_FUNC)
+#else
+#define API_TIMELINE_DURATION ASSERT(true)
+#define API_TIMELINE_BEGIN_END ASSERT(true)
+#endif
 
 #if defined(DEBUG)
 // An object visitor which will iterate over all the function objects in the