Read shell's PATH rather than make's to avoid warning logspam.

This applies the same change to AOSP's robolectric 3.1.1 as
what another change with the same Change-Id already applied
to internal versions of robolectric.

Bug: 70518982
Test: Visual inspection of the change only. Ran test at
      subsequent CL.
Change-Id: I491fede7f0a64e1da4e63052802fd153a8b76d3f
Merged-In: I491fede7f0a64e1da4e63052802fd153a8b76d3f
1 file changed