Telephony(MSIM): Fix framework dex2oat failure in ART mode.

Remove multisim check from ContextImpl class static initialisation block.
Multisim check calls SystemProperties.get() which invokes a native call
and causes dex2oat compilation to abort when using ART run time.

Change-Id: Idcfe0877162ba38ef7f2c625e8c126f82e13ce2c
CRs-Fixed: 574143