[BOLT][test] Update log.test and perf_test

Address noisy tests by:
- perf_test: bumping sampling frequency to maximum,
- log.test: matching Binary Function "main"

Author: aaupov

bolt/test/X86/log.test

@@ -6,7 +6,7 @@ RUN: yaml2obj %p/Inputs/blarge.yaml &> %t.exe
 RUN: llvm-bolt %t.exe -o %t.null --data %p/Inputs/blarge.fdata -v=2 \
 RUN:   --reorder-blocks=normal --print-finalized --log-file=%t.log  2>&1 \
 RUN:   | FileCheck --check-prefix=CHECK --allow-empty %s
-RUN: cat %t.log | FileCheck %s --check-prefix=CHECK-LOG
+RUN: FileCheck %s --check-prefix=CHECK-LOG --input-file %t.log
 
 CHECK-NOT: BOLT-INFO
 CHECK-NOT: BOLT-WARNING
@@ -16,4 +16,4 @@ CHECK-NOT: BOLT-ERROR
 CHECK-LOG: BOLT-INFO: Target architecture
 CHECK-LOG: BOLT-INFO: BOLT version
 CHECK-LOG: BOLT-INFO: basic block reordering modified layout
-CHECK-LOG:    Binary Function "usqrt"
+CHECK-LOG:    Binary Function "main"

bolt/test/perf2bolt/perf_test.test

@@ -3,15 +3,12 @@
 REQUIRES: system-linux, perf
 
 RUN: %clang %S/Inputs/perf_test.c -fuse-ld=lld -Wl,--script=%S/Inputs/perf_test.lds -o %t
-RUN: perf record -e cycles:u -o %t2 -- %t
+RUN: perf record -Fmax -e cycles:u -o %t2 -- %t
 RUN: perf2bolt %t -p=%t2 -o %t3 -nl -ignore-build-id 2>&1 | FileCheck %s
 
 CHECK-NOT: PERF2BOLT-ERROR
 CHECK-NOT: !! WARNING !! This high mismatch ratio indicates the input binary is probably not the same binary used during profiling collection.
 
 RUN: %clang %S/Inputs/perf_test.c -no-pie -fuse-ld=lld -o %t4
-RUN: perf record -e cycles:u -o %t5 -- %t4
-RUN: perf2bolt %t4 -p=%t5 -o %t6 -nl -ignore-build-id 2>&1 | FileCheck %s --check-prefix=CHECK-NO-PIE
-
-CHECK-NO-PIE-NOT: PERF2BOLT-ERROR
-CHECK-NO-PIE-NOT: !! WARNING !! This high mismatch ratio indicates the input binary is probably not the same binary used during profiling collection.
+RUN: perf record -Fmax -e cycles:u -o %t5 -- %t4
+RUN: perf2bolt %t4 -p=%t5 -o %t6 -nl -ignore-build-id 2>&1 | FileCheck %s