Skip internal keys' lookup in LRU for the DefaultCache. #1899

Job	Run time
PSV.Linux.22.04.gcc9.Cpplint	8m 24s
PSV.Linux.22.04.gcc13.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	9m 25s
PSV.iOS.MacOS13.Xcode15	12m 2s
PSV.Linux.22.04.clang	9m 11s
PSV.Linux.22.04.gcc11	8m 3s
PSV.MacOS13.Xcode16	6m 31s
PSV.Linux.22.04.gcc13	11m 58s
PSV.Win.VC2019	8m 59s
PSV.Linux.Android.22.04	5m 41s
PSV.iOS.MacOS14.Xcode15	7m 17s
PSV.iOS.MacOS13.Xcode16	6m 21s
PSV.Commit.Checker	7s
PSV.Linux.22.04.gcc9.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 12s
PSV.iOS.MacOS13.Xcode14	14m 45s
PSV.Linux.22.04.gcc11.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 10s
PSV.Linux.22.04.gcc9.Tests.CodeCov	5m 36s
PSV.MacOS13.Xcode15.x86_64	3m 31s
PSV.MacOS14.Xcode15	4m 14s
	2h 6m 27s

Provide feedback