Fix runtest.sh in frameworks/base/wifi

The "make" command seems no longer supported after syncing today to
TOT:

build/core/main.mk:13: Calling make directly is no longer supported.
build/core/main.mk:14: Either use 'envsetup.sh; m' or 'build/soong/soong_ui.bash --make-mode'

Made the fix as suggested above.

Bug: 138863873
Test: unit tests

Change-Id: I2e24da0195327b750a7438427ef5033bcd6f5373