Use new (std::nothrow) throughout

If code uses "normal" `new`, the compiler is allowed to assume that
`nullptr` is never returned, even if built with -fno-exceptions.

Use `new (std::nothrow)` throughout so that `nullptr` gets returned
and can (in some cases) be handled.

Bug: 215451239
Test: VtsAidlKeyMintTargetTest
Change-Id: If7206b738f0fa0427866d022359aa16257889a9e
5 files changed