The overflow handling code in TestResult is broken. It does not correctly compute the segment that should be shown after the overflow message, with the result that the .jtr file can grow unboundedly.

For example, see the sizes of these files:
$ wc -c build/jtreg/work/tools/javac/classfiles/attributes/annotations/*.jtr
  3141554 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForGenericMethodTest.jtr
 17815399 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForInnerAnnotationTest.jtr
 44383298 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForInnerClassTest.jtr
 43449160 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForInnerEnumTest.jtr
 29426696 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForInnerInterfaceTest.jtr
 39902534 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeAnnotationsForTopLevelClassTest.jtr
  2902884 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeParameterAnnotationsForGenericMethodTest.jtr
 22337944 build/jtreg/work/tools/javac/classfiles/attributes/annotations/RuntimeParameterAnnotationsTest.jtr