[BOLT][NFC] Print timers in perf2bolt invocation

When BOLT is run in AggregateOnly mode (perf2bolt), it exits with code
zero so destructors are not run thus TimerGroup never prints the timers.

Add explicit printing just before the exit to honor options requesting
timers (`--time-rewrite`, `--time-aggr`).

Test Plan: updated bolt/test/timers.c

Reviewers: ayermolo, maksfb, rafaelauler, dcci

Reviewed By: dcci

Pull Request: #101270

Author: aaupov

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -3200,6 +3200,7 @@ void RewriteInstance::processProfileData() {
   if (opts::AggregateOnly) {
     PrintProgramStats PPS(&*BAT);
     BC->logBOLTErrorsAndQuitOnFatal(PPS.runOnFunctions(*BC));
+    TimerGroup::printAll(outs());
     exit(0);
   }
 }

bolt/test/timers.c

@@ -3,13 +3,20 @@
 # RUN: link_fdata %s %t.exe %t.fdata
 # RUN: llvm-bolt %t.exe -o %t.null --data %t.fdata -w %t.yaml --time-rewrite \
 # RUN:   2>&1 | FileCheck %s
+# RUN: link_fdata %s %t.exe %t.preagg PREAGG
+# RUN: perf2bolt %t.exe -o %t.null -p %t.preagg --pa --time-rewrite \
+# RUN:   2>&1 | FileCheck %s --check-prefix=CHECK-P2B
 
 # CHECK-DAG: update metadata post-emit
 # CHECK-DAG: process section metadata
 # CHECK-DAG: process metadata pre-CFG
 # CHECK-DAG: process metadata post-CFG
 # CHECK-DAG: finalize metadata pre-emit
 
+# CHECK-P2B-DAG: process section metadata
+# CHECK-P2B-DAG: process metadata pre-CFG
+
 # FDATA: 0 [unknown] 0 1 main 0 1 0
+# PREAGG: B X:0 #main# 1 0
 */
 int main() { return 0; }