Revert "soong: upgrade Android platform to clang-r370808"

This reverts commit 4f49e359.

Causes test failures in ndk_translate.
Bug: 145807809
Bug: 145827049
Test: N/A
Change-Id: I8f42a15fec44475b74b1926c70bc98e03fe66f52
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>