Bug 1785162 - Disable all-process stalling in Nightly r=gsvelto

A recent patch for bug 965392 (now reverted) may have been causing
additional memory use and OOM-crashes. To confirm this, temporarily(?)
revert all-process stalling on Nightly to the main-process-only version
active between 2022-07-28 and 2022-08-25, to collect a few days' worth of
telemetry.

On Beta and later, there are no functional changes.

Differential Revision: https://phabricator.services.mozilla.com/D157124

memory/build/mozjemalloc.cpp

@@ -1389,8 +1389,12 @@ static inline bool ShouldStallAndRetry() {
   // on Windows mostly skips this in favor of directly calling ::VirtualAlloc(),
   // though, so it's probably not going to matter whether we stall here or not.)
   return true;
-#  elif defined(NIGHTLY_BUILD)
+#  elif 0 && defined(NIGHTLY_BUILD)
   // On Nightly, always stall, for experiment's sake (bug 1785162).
+  //
+  // This is temporarily disabled in order to confirm its effect on main-process
+  // OOMs, due to the possible confounding factor of bug 965392. (See discussion
+  // in bug 1785162 for more detail.)
   return true;
 #  else
   // In the main process, always stall.