[ycm] More robust detection of V8 checkout

Do not enforce the checkout to be called "v8".
Just check that there is a `.git` directory in it.

R=olivf@chromium.org

No-Try: true
Change-Id: I22f596206f713cb0d2f0213f0a859d398ec558bc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7782120
Reviewed-by: Olivier Flückiger <olivf@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#106664}

.ycm_extra_conf.py

@@ -63,14 +63,12 @@ def FindV8SrcFromFilename(filename):
     (String) Path of 'v8/', or None if unable to find.
   """
   curdir = os.path.normpath(os.path.dirname(filename))
-  while not (PathExists(curdir, 'v8') and PathExists(curdir, 'v8', 'DEPS')
-             and (PathExists(curdir, '.gclient')
-                  or PathExists(curdir, 'v8', '.git'))):
+  while not PathExists(curdir, '.git'):
     nextdir = os.path.normpath(os.path.join(curdir, '..'))
     if nextdir == curdir:
       return None
     curdir = nextdir
-  return os.path.join(curdir, 'v8')
+  return curdir
 
 
 def GetClangCommandFromNinjaForFilename(v8_root, filename):