Use more descriptive file names for auto-collected bugreports

Sample with extra debug logging:
03-14 24:32:09 V/BugreportCollector: Found storedP AFTER_EACH_FAILED_TESTCASE for relation AFTER and noun FAILED_TESTCASE
03-14 24:32:09 V/BugreportCollector: test is FooTest#testName1, noun is FAILED_TESTCASE
03-14 24:32:09 V/BugreportCollector: Grabbing bugreport.
03-14 24:32:09 V/BugreportCollector: About to grab bugreport for FAILED-FooTest#testName1; custom name is null.
03-14 24:32:09 V/BugreportCollector: Log name is bug-FAILED-FooTest#testName1.1331710329153.txt

Bug: 5532753
Change-Id: Ida90d99b8916c0b91ecc6dbad2088c45100ce584
3 files changed