Revert "Replace strtok_r() with C++-style android::base::Tokenize()"

Revert submission 1890098

Reason for revert: Breaks tests, b/206740783
Reverted Changes:
I71190c735:Add ParseFstabFromString(), remove ReadFstabFromFp...
Ic1dd0eb97:Replace strtok_r() with C++-style android::base::T...

Change-Id: I1eecdc43d504385b00caec17db626eb1d623c8ef
1 file changed