Create a build rule for compiling deps at the Java STS language level

This allows building the Java > 11 logic in google-java-format into the jar
regardless of what language level is configured for the entire build, and
then dynamically enabling it when running on a new enough JDK, while
remaining compatible with earlier JDK versions.

PiperOrigin-RevId: 490074589

Author: cushon

core/src/test/resources/com/google/googlejavaformat/java/testdata/B20844369.input

@@ -1,6 +1,6 @@
 public class B20844369 {
   private static final String ID_PATTERN =
-  // TODO(user): add min/max lengths for the numbers here, e.g. android ID
+  // TODO(daw): add min/max lengths for the numbers here, e.g. android ID
   "(?:(?<androidId>\\d+)\\+)?" // optional Android ID
       + "(?<type>\\d+)" // type
       + ":"

core/src/test/resources/com/google/googlejavaformat/java/testdata/B20844369.output

@@ -1,6 +1,6 @@
 public class B20844369 {
   private static final String ID_PATTERN =
-      // TODO(user): add min/max lengths for the numbers here, e.g. android ID
+      // TODO(daw): add min/max lengths for the numbers here, e.g. android ID
       "(?:(?<androidId>\\d+)\\+)?" // optional Android ID
           + "(?<type>\\d+)" // type
           + ":"