Remove previous toolchain versions

Remove 1.46.0 and 1.47.0

Bug: 176888219
Test: m
Change-Id: Ie3c85fec226b66c88c6c6add0be94b05f22dd29b
3900 files changed
tree: d1fd690f9fc6b86d1410dc67e67828151bfd8bfa
  1. bootstrap/
  2. darwin-x86/
  3. linux-x86/
  4. tests/
  5. Android.bp
  6. OWNERS