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.setCondition(userTryNode, AllEscape.class);
        }
        if (anyContinue) {
            semanticScope.setCondition(userTryNode, AnyContinue.class);
        }
        if (anyBreak) {
            semanticScope.setCondition(userTryNode, AnyBreak.class);
        }
    }
    /**
     * Visits a catch statement and defines a variable for the caught exception.
     * Checks: control flow, type validation
     */
    @Override
    public void visitCatch(SCatch userCatchNode, SemanticScope semanticScope) {
        ScriptScope scriptScope = semanticScope.getScriptScope();
        String symbol = userCatchNode.getSymbol();
        if (scriptScope.getPainlessLookup().isValidCanonicalClassName(symbol)) {
            throw userCatchNode.createError(
                new IllegalArgumentException("invalid catch declaration: type [" + symbol + "] cannot be a name")
            );
        }
        String canonicalTypeName = userCatchNode.getCanonicalTypeName();
        Class<?> type = scriptScope.getPainlessLookup().canonicalTypeNameToType(canonicalTypeName);
        if (type == null) {
            throw userCatchNode.createError(
                new IllegalArgumentException("invalid catch declaration: cannot resolve type [" + canonicalTypeName + "]")
            );
        }
        Location location = userCatchNode.getLocation();