Migrated GN targets ilbc_test, isac_api_test, isac_switch_samprate_test from webrtc/modules/audio_coding/codecs NOTRY=True NOPRESUBMIT=True BUG=webrtc:6191 Review-Url: https://codereview.webrtc.org/2270403002 Cr-Commit-Position: refs/heads/master@{#13953}