JDK-8376045 gives HotSpot the ability to infer ACC_STRICT_INIT from the @NullRestricted annotation, without it needing to be explicit in the class file.

With that change, tests that use @NullRestricted can stop using the @Strict annotation and prepare to adopt `!` in the future.

The language rules for `!` don't do anything to reorder field initializers. As a result, any tests with @NullRestricted fields in identity classes will have to be adjusted so that the field is initialized inside an explicit constructor, before an explicit super() call.

From a quick grep, here is where @NullRestricted gets used:
hotspot/jtreg/compiler: 203 uses
hotspot/jtreg/runtime: 125 uses
hotspot/jtreg/serviceability: 13 uses
micro: 38 uses
jdk: 23 uses