ANDROID: mm: avoid using vmacache in lockless vma search

When searching vma under RCU protection vmcache should be avoided because
a race with munmap() might result in finding a vma and placing it into
vmcache after munmap() removed that vma and called vmcache_invalidate.
Once that vma is freed, vmcache will be left with an invalid vma pointer.

Bug: 257443051
Change-Id: I62438305fcf5139974f4f7d3bae5b22c74084a59
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Lee Jones <joneslee@google.com>