Modules: removed "js vm init" during configuration parsing.

Modules: removed "js vm init" during configuration parsing.

Previously, a notice-level log message "js vm init %s: %p" was emitted
for each JS engine created during configuration parsing.  This message
leaked to the compiled-in default error log even when the user
explicitly configured logging elsewhere, because config-time logging
uses the initial cycle log whose file descriptor is opened before the
user's error_log directive takes effect.

The log message was used for VM deduplication tests. The tests are
updated to verify unique engine identifiers via HTTP and stream
responses instead of grepping for log messages.

This fixes #1042 issue on Github.