Rename LruCache -> LegacyLruCache

There is a naming conflict with common/lru.h
and gd/common/lru_cache.h.  In order to make the
metrics calls from the shim on the actual events
the legacy version has been renamed to reflect.

Bug: 162984360
Tag: #gd-refactor
Test: cert/run --host SecurityTest
Test: atest --host bluetooth_test_gd
Test: Manual testing with hybrid stack
Change-Id: I4e8656915359fb29b57dcd8405ee295d8ab2a536