RFR: 8292202: modules_do is called without Module_lock [v3]

[Calvin Cheung]

> Please review this fix which involves:
> 
> - acquire the `Module_lock` before calling `modules_do`;
> - move the call to `ClassLoader::setup_module_search_path `out of `do_module`;
> - save the module paths in a `GrowableArray` in `do_module` for calling `ClassLoader::setup_module_search_path`.
> 
> Passed tiers 1 - 3 testing.

Calvin Cheung has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - add assert in modules_do functions
 - Merge branch 'master' into 8292202-modules_do
 - get rid of the _total_count field
 - 8292202: modules_do is called without Module_lock

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/10291/files
  - new: https://git.openjdk.org/jdk/pull/10291/files/9f4e67f9..a3ebd5b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10291&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10291&range=01-02

  Stats: 99962 lines in 1838 files changed: 46911 ins; 41369 del; 11682 mod
  Patch: https://git.openjdk.org/jdk/pull/10291.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10291/head:pull/10291

PR: https://git.openjdk.org/jdk/pull/10291