CFG for while (true)

[mernst]

The CFG generator should treat true specially when used as a while condition.

Consider the following class:

public class WhileTrueInitialization {

  private final double field;

  WhileTrueInitialization() {
    double local;
    while (true) {
      local = 1;
      break;
    }
    field = local;
  }
}

Running

javacheck -g WhileTrueInitialization.java -processor nullness

yields

WhileTrueInitialization.java:11: error: [assignment.type.incompatible] incompatible types in assignment.
    field = local;
            ^
  found   : @UnknownInitialization @NonNull double
  required: @Initialized @NonNull double
1 error

The problem is apparent from viewing the control flow graph: while (true) is treated like any other while construct in that there is a branch that skips the entire body. That is not possible when the condition is true, so the CFG should not include that branch.

This is a duplicate of #1727, but with a smaller test case.