[vm] Report the current sanitizer in the compiler environment.

TEST=ci
Change-Id: I56585a1fdb1bb6b92eab706fd0a66f78888bc55d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/464620
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

utils/aot_snapshot.gni

@@ -92,12 +92,13 @@ template("aot_snapshot") {
       # (Instead of ensuring every user of the "application_snapshot" /
       # "kernel_snapshot" passes this if needed, we always pass it)
       "-Dsdk_hash=$sdk_hash",
+      "-Ddart.vm.product=$product_mode",
+      "-Ddart.vm.asan=$is_asan",
+      "-Ddart.vm.msan=$is_msan",
+      "-Ddart.vm.tsan=$is_tsan",
     ]
     args += gen_kernel_args
     args += [ rebase_path(main_dart, root_build_dir) ]
-    if (product_mode) {
-      args += [ "-Ddart.vm.product=true" ]
-    }
     if (defined(invoker.args)) {
       args += invoker.args
     }

utils/application_snapshot.gni

@@ -168,6 +168,9 @@ template("application_snapshot") {
       # "kernel_snapshot" passes this if needed, we always pass it)
       "-Dsdk_hash=$sdk_hash",
       "-Ddart.vm.product=$is_product_flag",
+      "-Ddart.vm.asan=$is_asan",
+      "-Ddart.vm.msan=$is_msan",
+      "-Ddart.vm.tsan=$is_tsan",
     ]
     args += gen_kernel_args
     args += [ rebase_path(main_dart, root_build_dir) ]