Fix MacOS build breakage

runtime/vm/os_macos.cc

Index: runtime/vm/os_macos.cc
diff --git a/runtime/vm/os_macos.cc b/runtime/vm/os_macos.cc
index 31bb3e86917d944d10b6d5530bb02d665486e344..f8c7caf2c410dcc58974af05f663c39f0393f246 100644
--- a/runtime/vm/os_macos.cc
+++ b/runtime/vm/os_macos.cc
@@ -159,7 +159,7 @@ int64_t OS::GetCurrentThreadCPUMicros() {
       (info->system_time.seconds + info->user_time.seconds);
   thread_cpu_micros *= kMicrosecondsPerSecond;
   thread_cpu_micros += info->user_time.microseconds;
-  thread_cpu_micros += info->system_time.microseconds
+  thread_cpu_micros += info->system_time.microseconds;
   return thread_cpu_micros;
 #endif  // TARGET_OS_IOS
 }