[PATCH 00/10] pickaxe: honor -i when used with -S and --pickaxe-regex; cleanups

This series allows the options -i/--regexp-ignore-case, --pickaxe-regex, and -S to be used together and work as expected to perform a pickaxe search using case-insensitive regular expression matching. Its first half refactors the test script and extends test coverage a bit while we're at it. The actual change is in the sixth patch. It enables the two following cleanups. The last two patches are independent simple cleanups.

  t4209: set up expectations up front
  t4209: factor out helper function test_log()
  t4209: factor out helper function test_log_icase()
  t4209: use helper functions to test --grep
  t4209: use helper functions to test --author
  pickaxe: honor -i when used with -S and --pickaxe-regex
  pickaxe: merge diffcore_pickaxe_grep() and diffcore_pickaxe_count()
    into diffcore_pickaxe()
  pickaxe: move pickaxe() after pickaxe_match()
  pickaxe: call strlen only when necessary in diffcore_pickaxe_count()
  pickaxe: simplify kwset loop in contains()

 diffcore-pickaxe.c     | 142 +++++++++++++++++--------------------------
 t/t4209-log-pickaxe.sh | 159 +++++++++++++++++--------------------------------
 2 files changed, 110 insertions(+), 191 deletions(-)