RFR: 8292202: modules_do is called without Module_lock [v2]

[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 incrementally with one additional commit since the last revision:

  get rid of the _total_count field

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10291/files
  - new: https://git.openjdk.org/jdk/pull/10291/files/46fc54a0..9f4e67f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10291&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10291&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 1 del; 2 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