v8: add missing ',' in OpenBSD's 'sources' section.

Add stack_trace_posix to 'sources' as well.

Fixes #15784
Fixes nodejs/help#992

add stack_trace_posix to OpenBSD's sources

PR-URL: #18448
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

deps/v8/src/v8.gyp

@@ -2044,9 +2044,10 @@
                 '-L/usr/local/lib -lexecinfo',
             ]},
             'sources': [
+              'base/debug/stack_trace_posix.cc',
               'base/platform/platform-openbsd.cc',
               'base/platform/platform-posix.h',
-              'base/platform/platform-posix.cc'
+              'base/platform/platform-posix.cc',
               'base/platform/platform-posix-time.h',
               'base/platform/platform-posix-time.cc',
             ],