Using deprecated API on Java 7

[Date class](https://github.com/HaxeFoundation/haxe/blob/development/std/Date.hx) using deprecates. It happing when compiling with Java 7 (`1.7.0_71`).

```
/usr/bin/haxe haxelib.hxml
haxelib run hxjava hxjava_build.txt --haxe-version 3200
javac "-sourcepath" "src" "-d" "obj" "-g:none" "@cmd"
Note: src/haxe/root/Date.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

Process finished with exit code 0
```

Start with std/Date.hx and inspect how it is translated for Java 7. Reproduce the report using haxelib.hxml and the shown hxjava build command, then verify that compiling with Java 7 no longer reports deprecated API usage.

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