raw2trace WARNING while processing trace collected with -trace_after_instrs and -trace_for_instrs

**Describe the bug**
I am tracing threadsig.cpp (from https://raw.githubusercontent.com/DynamoRIO/drmemtrace_samples/master/threadsig.x86_64/threadsig.cpp). I am seeing the warning shown below while running raw2trace.

```
$ build/clients/bin64/drraw2trace -jobs 1 -indir drmemtrace.threadsig.200649.7844.dir/
WARNING: Input file for thread 200651 is truncated
```

**To Reproduce**
```
$ build/bin64/drrun -t drcachesim -trace_after_instrs 2000M -trace_for_instrs 10K -verbose 0 --offline -- ./threadsig 2 20000000

<(1+x) Handling our fault in a TRY at 0x00007f79f3734199>
Hit delay threshold: enabling tracing.
Hit tracing window #0 limit: disabling tracing.

Estimation of pi is 3.141592653589820
Received 8200 alarms

```
Please also answer these questions:
- What happens when you run without any client?
- Not applicable since the issue is with the drcachesim client, but the program runs fine without any client
- What happens when you run with debug build ("-debug" flag to drrun/drconfig/drinject)?
- This was run with debug build. I didn't try the release build

**Expected behavior**
No warning expected.

**Screenshots or Pasted Text**

**Versions**
- What version of DynamoRIO are you using?
- b114a32e65ece7a6cbf8d9eee9ae779b3c78e567
- Does the latest build from https://github.com/DynamoRIO/dynamorio/releases solve the problem?
- No
- What operating system version are you running on? ("Windows 10" is *not* sufficient: give the release number.)
- Ubuntu 18.04.6 LTS
- Is your application 32-bit or 64-bit?
- 64-bit

**Additional context**
Add any other context about the problem here.