If a hex literal has an 'd' of 'f' in it, such as '0xf' or '0xd', the compiler fails with illegal tree structure.

The other hex literals work.  The issue is probably related to using `f` and `d` in float and double literals.

```
    public void testHexCollisionDouble() {
        assertEquals(13, exec("return 0xd"));
    }

    public void testHexCollisionFloat() {
        assertEquals(15, exec("return 0xf"));
    }

    public void testHex() throws Exception {
        for (int i = 0; i <= 15; i++) {
            String hex = Integer.toHexString(i);
            if ("d".equals(hex) || "f".equals(hex)) {
                continue;
            }
            assertEquals(i, exec("return 0x" + hex));
            assertEquals(i, exec("return 0x" + hex.toUpperCase(Locale.ROOT)));
            assertEquals(i, exec("return 0X" + hex));
            assertEquals(i, exec("return 0X" + hex.toUpperCase(Locale.ROOT)));
        }
    }
```
modules/lang-painless/src/main/java/org/elasticsearch/painless/phase/DefaultSemanticAnalysisPhase.java
semanticScope.putDecoration(userCallLocalNode, new StandardConstant(classBindingOffset));
            scriptScope.markNonDeterministic(classBinding.annotations().containsKey(NonDeterministicAnnotation.class));
            typeParameters = new ArrayList<>(classBinding.typeParameters());
            valueType = classBinding.returnType();
        } else if (instanceBinding != null) {
            semanticScope.putDecoration(userCallLocalNode, new StandardPainlessInstanceBinding(instanceBinding));
            typeParameters = new ArrayList<>(instanceBinding.typeParameters());
            valueType = instanceBinding.returnType();
        } else {
            throw new IllegalStateException("Illegal tree structure.");
        }
        
        
        
        for (int argument = 0; argument < userArgumentsSize; ++argument) {
            AExpression userArgumentNode = userArgumentNodes.get(argument);
            semanticScope.setCondition(userArgumentNode, Read.class);
            semanticScope.putDecoration(userArgumentNode, new TargetType(typeParameters.get(argument + classBindingOffset)));
            semanticScope.setCondition(userArgumentNode, Internal.class);
            checkedVisit(userArgumentNode, semanticScope);
            decorateWithCast(userArgumentNode, semanticScope);
        }
        semanticScope.putDecoration(userCallLocalNode, new ValueType(valueType));
    }
    /**
     * Visits a boolean constant expression.
     * Checks: type validation
     */
    @Override
    public void visitBooleanConstant(EBooleanConstant userBooleanConstantNode, SemanticScope semanticScope) {