ASuite: remove _py3_ in target names.

Atest has fully migrated to py3, and this CL is for cleanup redundant
_py3_ pattern of relavent target names.

Bug: 176775670

Test: m atest
m aidegen
m asuite_metrics_lib_tests
m asuite_cc_lib_tests

Change-Id: I236a66689c074c9fd21e8a76e3d1c3327697c195
4 files changed