Add contents property to art-bootclasspath-fragment

Adds coverage properties too so that the contents are consistent with
the configuration even when EMMA_INSTRUMENT_FRAMEWORK=true.

Bug: 177892522
Test: m nothing
      m EMMA_INSTRUMENT=true EMMA_INSTRUMENT_FRAMEWORK=true nothing
Change-Id: I2060c99c510a36dfbfce57dfd72b336841ff1ff3
1 file changed