Remove deprecated WITH_HOST_DALVIK.
Remove deprecated WITH_HOST_DALVIK.

Switch host build to clang as conscrypt uses C++11 and not all GCC
host compilers support it.

Bug: 13751317
Change-Id: I74ffdda695e47967b61a133c8b6fc52f6547a3a0
google/conscrypt,google/conscrypt,google/conscrypt,google/conscrypt,google/conscrypt,google/conscrypt