fix(scripts): Set target.'cfg(all())'.rustflags in cargo-simtest

e need to use target.'cfg(all())'.rustflags instead of build.rustflags
because the latter are ignored if any target flags are set.

scripts/simtest/cargo-simtest

@@ -103,7 +103,7 @@ root_dir=$(git rev-parse --show-toplevel)
 export SIMTEST_STATIC_INIT_MOVE=$root_dir"/examples/move/basics"
 
 cargo ${CARGO_COMMAND[@]} \
-  --config "build.rustflags = [$RUST_FLAGS]" \
+  --config "target.'cfg(all())'.rustflags = [$RUST_FLAGS]" \
   "${cargo_patch_args[@]}" \
   "$@"