getCauseStackTraceLines throws StringIndexOutOfBoundsException

### Description
Exception in the test runner

### Steps to Reproduce
Generate a failure during a test

### Expected Results
Test orchestrator generate the test report successfully

### Actual Results
This is the stacktrace that shows the exception:

```
10-28 12:00:57.213 7455 7485 E TestRunner: java.lang.StringIndexOutOfBoundsException: length=117; index=290
10-28 12:00:57.213 7455 7485 E TestRunner: at java.lang.String.substring(String.java:1999)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.services.events.internal.Throwables.getCauseStackTraceLines(Throwables.java:70)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.services.events.internal.Throwables.getTrimmedStackTrace(Throwables.java:38)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.services.events.internal.StackTrimmer.getTrimmedStackTrace(StackTrimmer.java:37)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.services.events.ParcelableConverter.getFailure(ParcelableConverter.java:106)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.services.events.ParcelableConverter.getFailuresFromList(ParcelableConverter.java:119)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.internal.events.client.OrchestratedInstrumentationListener.testRunFinished(OrchestratedInstrumentationListener.java:84)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.notification.SynchronizedRunListener.testRunFinished(SynchronizedRunListener.java:42)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.notification.RunNotifier$2.notifyListener(RunNotifier.java:103)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.notification.RunNotifier$SafeNotifier.run(RunNotifier.java:72)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.notification.RunNotifier.fireTestRunFinished(RunNotifier.java:100)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.JUnitCore.run(JUnitCore.java:138)
10-28 12:00:57.213 7455 7485 E TestRunner: at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:68)
10-28 12:00:57.213 7455 7485 E TestRunner: at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:59)

```

### AndroidX Test and Android OS Versions
androidx.test:runner:1.6.2 on API 28

### Link to a public git repo demonstrating the problem:

Start by reading androidx.test.services.events.internal.Throwables.getCauseStackTraceLines at Throwables.java:70, then trace its callers through getTrimmedStackTrace, StackTrimmer.getTrimmedStackTrace, and ParcelableConverter.getFailure. Reproduce the failure from the supplied stack trace on API 28 and verify that generating a test failure report no longer throws StringIndexOutOfBoundsException.

Written by the indexing model from the issue text.