Imports within try blocks are hoisted incorrectly

### Problem

Microbundle hoists a `require()` call out of a `try {}` block in a dependency. When that `require()` call throws, it is not caught by the `try {}` block anymore.

I'm not sure whether this is an issue with microbundle or rollup. A solution to this would be not to hoist `require()` calls if they are in a nested block or wrap them in a function to evaluate them lazily.

### How to reproduce

Make sure you have `yarn` installed globally, then run following commands:

```sh
mkdir bug-test
cd bug-test
yarn add microbundle esm
echo "import 'esm'" > test.js
yarn microbundle test.js --format cjs --target node --external none
node dist/bug-test.js
```

### Expected behaviour

Commands above should execute and exit without error code.

### Actual behaviour

The `node dist/bug-test.js` command throws this error:

```
internal/modules/cjs/loader.js:969
throw err;
^

Error: Cannot find module 'internal/bootstrap/loaders'
Require stack:
- /Users/dany/code/bug-test/dist/bug-test.js
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:966:15)
at Function.Module._load (internal/modules/cjs/loader.js:842:27)
at Module.require (internal/modules/cjs/loader.js:1026:19)
at require (internal/modules/cjs/helpers.js:72:18)
at Object. (/Users/dany/code/bug-test/dist/bug-test.js:7:31)
at Module._compile (internal/modules/cjs/loader.js:1138:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1158:10)
at Module.load (internal/modules/cjs/loader.js:986:32)
at Function.Module._load (internal/modules/cjs/loader.js:879:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12) {
code: 'MODULE_NOT_FOUND',
requireStack: [ '/Users/dany/code/bug-test/dist/bug-test.js' ]
```

The reason for this error is that there is this code in the `esm` module:

```js
[…] function q(e){let t;try{const{internalBinding:n}=require("internal/bootstrap/loaders"),r=n("natives");x(r,e)&&(t=r[e])}catch(e){}return"string"==typeof t?t:""} […]

// Simplified:
try { require("internal/bootstrap/loaders") } catch (e) {}
```

which is modified to this by microbundle in `dist/bug-test.js`:

```js
[…] var loaders = _interopDefault(require('internal/bootstrap/loaders')); […] function q(e){let t;try{const{internalBinding:n}=loaders,r=n("natives");x(r,e)&&(t=r[e]);}catch(e){}return "string"==typeof t?t:""} […]

// Simplified:
var loaders = require("internal/bootstrap/loaders")
try { loaders } catch (e) {}
```

### Additional info

microbundle v0.12.0
Node v12.17.0
Mac OS 10.15.5
Related: https://github.com/nodejs/node/issues/33656

Start by running the reproduction commands with microbundle v0.12.0 on Node v12.17.0, then inspect dist/bug-test.js and compare the generated require placement with the source snippet from esm. Determine whether the hoisting originates in microbundle or Rollup; done means the require remains protected by the try block and node dist/bug-test.js exits without an error.

Scritto dal modello di indicizzazione a partire dal testo della issue.