[vm] Turn on entry point checking in JIT mode.
Now that Flutter tests that access entry points from native code
have been annotated[1], we can turn on entry point checking in JIT
mode.
This CL also removes the A flag category from flag_list.h and the
AOT_FLAG_MACRO definitions and uses from flags.[cc,h], as they were
created as a temporary measure until this flag could be unconditionally
defaulted to true.
[1] See the following PRs:
* https://github.com/flutter/engine/pull/57158
* https://github.com/flutter/flutter/pull/160158
* https://github.com/flutter/flutter/pull/160421
TEST=vm/dart/entrypoints_verification_test vm/cc/IRTest
vm/cc/StreamingFlowGraphBuilder vm/cc/STC vm/cc/TTS
Issue: https://github.com/dart-lang/sdk/issues/50649
Issue: https://github.com/flutter/flutter/issues/118608
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-product-x64-try,vm-aot-linux-debug-x64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-product-arm64-try,vm-aot-dwarf-linux-product-x64-try,vm-linux-debug-x64-try,vm-linux-release-x64-try,vm-appjit-linux-product-x64-try
Change-Id: Ibe5b21bb74f1a6fb88824b71ff87b9e555216dbf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/400301
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
Tess Strickland
982b9fad44