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
);
                            }
                            if (setter != null && (setter.returnType() != void.class || setter.typeParameters().size() != 1)) {
                                throw userDotNode.createError(
                                    new IllegalArgumentException(
                                        "Illegal set shortcut on field [" + index + "] for type [" + prefixCanonicalTypeName + "]."
                                    )
                                );
                            }
                            if (getter != null && setter != null && setter.typeParameters().get(0) != getter.returnType()) {
                                throw userDotNode.createError(new IllegalArgumentException("Shortcut argument types must match."));
                            }
                            if ((read == false || getter != null) && (write == false || setter != null)) {
                                valueType = setter != null ? setter.typeParameters().get(0) : getter.returnType();
                            } else {
                                throw userDotNode.createError(
                                    new IllegalArgumentException(
                                        "Illegal shortcut on field [" + index + "] for type [" + prefixCanonicalTypeName + "]."
                                    )
                                );
                            }
                            if (getter != null) {
                                semanticScope.putDecoration(userDotNode, new GetterPainlessMethod(getter));
                            }
                            if (setter != null) {
                                semanticScope.putDecoration(userDotNode, new SetterPainlessMethod(setter));
                            }
                            semanticScope.setCondition(userDotNode, Shortcut.class);
                        } else if (isStatic == false) {
                            if (Map.class.isAssignableFrom(prefixValueType.valueType())) {