camera2: add more tests for reprocessing

Add a test for recreating reprocessing sessions and a test for
cross session capture exceptions. Also increase the number of
reprocess captures for non-basic tests and refactor the test
code to be shared by different test cases.

Bug: 20263212
Change-Id: I2b533a5f6fc6715fa596575768ad2e309e36f07c
1 file changed