Re-implement mma/mmma using make goals.

Previously we use command line variable BUILD_MODULES_IN_PATHS which
causes kati to regenerate build.ninja if any variable value changes.

TODO: Remove the old rules of BUILD_MODULES_IN_PATHS in
build/core/main.mk and ninja.mk once users have re-sourced envsetup.sh.
Probably in a few weeks.

Caveat: With this change, if a user sources the new envsetup.sh, mma/mmma
won't work in old branches from the same shell.

Bug: 24309760
Change-Id: I212e82aeebaaa2bd4114e2066f1995da8886b5e2