No longer call `make` directly in build/apex/runtests.sh

This is no longer supported since
https://android-review.googlesource.com/c/platform/build/+/1092954/.

Use `build/soong/soong_ui.bash --make-mode` instead.

Test: art/build/apex/runtests.sh
Bug: 138711335
Change-Id: I803610dca0c07f832b3f8330964fa05089024668
1 file changed