deps: backport ec1ffe3 from upstream V8

This commit adds lldbinit files from upstream V8 and also adds these so
that they get installed when `make install` is run.

Original commit message:

[tools] add lldbinit

    The goal of this commit is to add the equivalent to gdbinit but
    for lldb. I've tried to replicate the commands as close as possible
    but I'm unsure about the jss command and hoping to get some feedback
    on it in addition to the bta command which I'm not sure how/when
    this could be used. This is probably just inexperience on my part.

    The lldbinit file can be placed into a directory prefixed with dot
    (.lldbinit) and the python script is currently expected to be in the
    same directory. The path to the script can be changed manually if
    needed as well.

    NOTRY=true

    Review-Url: https://codereview.chromium.org/2758373002
    Cr-Commit-Position: refs/heads/master@{#44136}

PR-URL: https://github.com/nodejs/node/pull/12061
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

tools/install.py

@@ -133,6 +133,8 @@ def files(action):
   action(['src/node.stp'], 'share/systemtap/tapset/')
 
   action(['deps/v8/tools/gdbinit'], 'share/doc/node/')
+  action(['deps/v8/tools/lldbinit'], 'share/doc/node/')
+  action(['deps/v8/tools/lldb_commands.py'], 'share/doc/node/')
 
   if 'freebsd' in sys.platform or 'openbsd' in sys.platform:
     action(['doc/node.1'], 'man/man1/')