For LLVM, uses the debugtrap intrinsic which is more debugging specific
than the trap intrinsic. The Subzero implementationuses a Trap
intrinsic. Both translate to 'int 3' on x86.

Bug: b/135997638
Change-Id: I6eca71e74752c4646baeade9a39b338e17053336
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/33369Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>