prog: fix a data race

The race initially showed up on the new benchmark (see race report below).
The race indicated a wrong call passed to replaceArg,
as the result we sanitized the wrong call and left the new call un-sanitized.

Fix this.
Add test that exposes this.
Run benchmarks in race mode during presubmit
(benchmarks have higher chances of uncovering races than tests).

WARNING: DATA RACE
Write at 0x00c42000d3f0 by goroutine 18:
  github.com/google/syzkaller/sys/linux.(*arch).sanitizeCall()
      sys/linux/init.go:155 +0x256
  github.com/google/syzkaller/sys/linux.(*arch).(github.com/google/syzkaller/sys/linux.sanitizeCall)-fm()
      sys/linux/init.go:42 +0x4b
  github.com/google/syzkaller/prog.(*Prog).replaceArg()
      prog/prog.go:357 +0x239
  github.com/google/syzkaller/prog.generateHints.func2()
      prog/hints.go:105 +0x124
  github.com/google/syzkaller/prog.checkConstArg()
      prog/hints.go:128 +0xf3
  github.com/google/syzkaller/prog.generateHints()
      prog/hints.go:120 +0x495
  github.com/google/syzkaller/prog.(*Prog).MutateWithHints.func1()
      prog/hints.go:72 +0x67
  github.com/google/syzkaller/prog.foreachSubargImpl.func1()
      prog/analysis.go:86 +0x9f
  github.com/google/syzkaller/prog.foreachSubargImpl()
      prog/analysis.go:104 +0xc8
  github.com/google/syzkaller/prog.foreachArgArray()
      prog/analysis.go:113 +0x89
  github.com/google/syzkaller/prog.foreachArg()
      prog/analysis.go:121 +0x50
  github.com/google/syzkaller/prog.(*Prog).MutateWithHints()
      prog/hints.go:71 +0x18e
  github.com/google/syzkaller/prog.BenchmarkHints.func1()
      prog/hints_test.go:477 +0x77
  testing.(*B).RunParallel.func1()
      testing/benchmark.go:626 +0x156

Previous read at 0x00c42000d3f0 by goroutine 17:
  github.com/google/syzkaller/prog.clone()
      prog/clone.go:38 +0xbaa
  github.com/google/syzkaller/prog.(*Prog).cloneImpl()
      prog/clone.go:21 +0x17f
  github.com/google/syzkaller/prog.generateHints()
      prog/hints.go:95 +0xd0
  github.com/google/syzkaller/prog.(*Prog).MutateWithHints.func1()
      prog/hints.go:72 +0x67
  github.com/google/syzkaller/prog.foreachSubargImpl.func1()
      prog/analysis.go:86 +0x9f
  github.com/google/syzkaller/prog.foreachSubargImpl()
      prog/analysis.go:104 +0xc8
  github.com/google/syzkaller/prog.foreachArgArray()
      prog/analysis.go:113 +0x89
  github.com/google/syzkaller/prog.foreachArg()
      prog/analysis.go:121 +0x50
  github.com/google/syzkaller/prog.(*Prog).MutateWithHints()
      prog/hints.go:71 +0x18e
  github.com/google/syzkaller/prog.BenchmarkHints.func1()
      prog/hints_test.go:477 +0x77
  testing.(*B).RunParallel.func1()
      testing/benchmark.go:626 +0x156

1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 4ef3b4585..5ea34c242 100644
--- a/Makefile
+++ b/Makefile
@@ -219,7 +219,7 @@ tidy:
 
 test:
 	$(GO) test -short ./...
-	$(GO) test -short -race ./...
+	$(GO) test -short -race -bench=.* ./...
 
 arch:
 	env GOOG=darwin GOARCH=amd64 go install github.com/google/syzkaller/syz-manager