4044: [code coverage] Merge script changes for separated test types.

- When merging profraw to profdata at shard_merge: Accept the test
target name arg from input and name the profdata file as
{target_name}.profdata.
- When merging profdata from different target to one profdata, add
support to filter the input with a regex pattern. This will be used to
merge only profdata of needed test type.

(cherry picked from commit 0c2093e58c56ebfd9dbf3a359f7df4da223a22a9)

Bug: 1064785
Change-Id: I4c8ff800c7b40adef2cfe8f905204d6d3ec87ae8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2121087
Commit-Queue: Zhaoyang Li <zhaoyangli@chromium.org>
Reviewed-by: Sajjad Mirza <sajjadm@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#754564}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135160
Cr-Commit-Position: refs/branch-heads/4044@{#893}
Cr-Branched-From: a6d9daf149a473ceea37f629c41d4527bf2055bd-refs/heads/master@{#737173}