trusty:kernel: Improve BTI test.

Use assembly to get callee function addresses to prevent veneers from
the compiler interfering with BTI landing pad tests.

Bug: 260397427
Test: build.py qemu-generic-arm64-test-debug
Test: build.py qemu-generic-arm32-test-debug
Test: Run tests on QEMU 7 with cpu max (supports BTI)
Test: Run tests on ARM hardware (supports BTI)
Change-Id: Ieda4726e1641b527a3ab62306f858fa13a2aad09
3 files changed