[perf2bolt] Relax rules for aggregation in strict mode

Summary:
While aggregating perf.data events, even in strict mode, there is no
need to process all functions since we are not generating an output
binary. However, it's still important to convert data for as many
functions as possible, even for ones with unknown internal control flow.

(cherry picked from FBD22248390)

bolt/src/RewriteInstance.cpp

@@ -403,8 +403,11 @@ bool isHotTextMover(const BinaryFunction &Function) {
   return false;
 }
 
-/// Return true if we can process the binary without processing all functions.
+/// Return true if we should process all functions in the binary.
 bool processAllFunctions() {
+  if (opts::AggregateOnly)
+    return false;
+
   if (UseOldText || StrictMode)
     return true;