Replace CHECK(x && y) with two separate CHECK() calls

That way, the debug printout will tell us which of x and y that was false.

BUG=none

Review-Url: https://codereview.webrtc.org/2988153003
Cr-Commit-Position: refs/heads/master@{#19297}
diff --git a/webrtc/rtc_base/macutils.cc b/webrtc/rtc_base/macutils.cc
index 282f782..2e5e1fb 100644
--- a/webrtc/rtc_base/macutils.cc
+++ b/webrtc/rtc_base/macutils.cc
@@ -72,7 +72,9 @@
 }
 
 static bool GetOSVersion(int* major, int* minor, int* bugfix) {
-  RTC_DCHECK(major && minor && bugfix);
+  RTC_DCHECK(major);
+  RTC_DCHECK(minor);
+  RTC_DCHECK(bugfix);
   struct utsname uname_info;
   if (uname(&uname_info) != 0)
     return false;