Adjacent sibling combinator no longer working

### Current behavior

Adjacent sibling combinator `(input#ProgramName + .invalidMessage)` no longer returning the adjacent sibling.

ran against

```html

```

### Expected behavior

Return the Adjacent sibling

### Your environment

Windows 10 Pro
npm: '6.11.1',
ares: '1.15.0',
cldr: '33.1',
http_parser: '2.8.0',
icu: '62.1',
modules: '64',
napi: '3',
nghttp2: '1.34.0',
node: '10.15.3',
openssl: '1.1.0j',
tz: '2018e',
unicode: '11.0',
uv: '1.23.2',
v8: '6.8.275.32-node.51',
zlib: '1.2.11'

Output from `npm ls --depth=0` _some values filtered to shorten the list_
+-- chalk@2.4.1
+-- css-loader@1.0.0
+-- enzyme@3.10.0
+-- enzyme-adapter-react-16@1.15.1
+-- file-loader@2.0.0
+-- fs-extra@7.0.0
+-- html-webpack-plugin@4.0.0-alpha.2
+-- identity-obj-proxy@3.0.0
+-- jest@24.9.0
+-- jest-pnp-resolver@1.0.1
+-- jest-resolve@23.6.0
+-- mini-css-extract-plugin@0.4.3
+-- node-sass@4.13.0
+-- optimize-css-assets-webpack-plugin@5.0.1
+-- pnp-webpack-plugin@1.1.0
+-- prop-types@15.7.2
+-- react@16.12.0
+-- react-app-polyfill@0.1.3
+-- react-dev-utils@6.1.1
+-- react-dom@16.12.0
+-- resolve@1.8.1
+-- webpack@4.19.1

#### API

- [ ] shallow
- [x] mount
- [ ] render

#### Version

| library | version
| ------------------- | -------
| enzyme | 3.10.0
| react | 16.12.0
| react-dom | 16.12.0
| jest | 24.9.0
| adapter (below) |

#### Adapter

- [ ] enzyme-adapter-react-16
- [ ] enzyme-adapter-react-16.3
- [ ] enzyme-adapter-react-16.2
- [x] enzyme-adapter-react-16.1
- [ ] enzyme-adapter-react-15
- [ ] enzyme-adapter-react-15.4
- [ ] enzyme-adapter-react-14
- [ ] enzyme-adapter-react-13
- [ ] enzyme-adapter-react-helper
- [ ] others ( )

Reproduce the issue with Enzyme's mount API using the supplied HTML structure and the adjacent sibling selector `(input#ProgramName + .invalidMessage)`. Compare the selector result with the expected adjacent div and confirm the behavior across the listed React and adapter versions; done means the adjacent sibling is returned.

Written by the indexing model from the issue text.