Unused import bundled unless define test is on same line for class methods only

When given a define, esbuild is able to treeshake some known dead code. This does not work for class methods unless the define is tested on the same line.

```
esbuild --bundle --format=esm --minify --tree-shaking --define:debug=false entry.ts
```

```ts
import {a, b} from './file.ts'

class C {
init(): void {
if (!debug) return
if (debug) a()
b()
}
}

new C()
```

```ts
export function a(): void {
console.log('a')
}

export function b(): void {
console.log('b')
}
```

Produces `function i(){console.log("b")}var o=class{init(){}};new o;` when no logs were expected `var o=class{init(){}};new o;`.

It seems to be method specific. [This code shakes fine](https://esbuild.github.io/try/#YgAwLjI1LjAALS1idW5kbGUgLS1mb3JtYXQ9ZXNtIC0tbWluaWZ5IC0tdHJlZS1zaGFraW5nIC0tZGVmaW5lOmRlYnVnPWZhbHNlAGUAZW50cnkudHMAaW1wb3J0IHthLCBifSBmcm9tICcuL2ZpbGUudHMnCgpmdW5jdGlvbiAgaW5pdCgpOiB2b2lkIHsKICBpZiAoIWRlYnVnKSByZXR1cm4KICBpZiAoZGVidWcpIGEoKQogIGIoKQp9Cgppbml0KCkAAGZpbGUudHMAZXhwb3J0IGZ1bmN0aW9uIGEoKTogdm9pZCB7CiAgY29uc29sZS5sb2coJ2EnKQp9CgpleHBvcnQgZnVuY3Rpb24gYigpOiB2b2lkIHsKICBjb25zb2xlLmxvZygnYicpCn0):

```ts
import {a, b} from './file.ts'

function init(): void {
if (!debug) return
if (debug) a()
b()
}

init()
```

[Playground](https://esbuild.github.io/try/#YgAwLjI1LjAALS1idW5kbGUgLS1mb3JtYXQ9ZXNtIC0tbWluaWZ5IC0tdHJlZS1zaGFraW5nIC0tZGVmaW5lOmRlYnVnPWZhbHNlAGUAZW50cnkudHMAaW1wb3J0IHthLCBifSBmcm9tICcuL2ZpbGUudHMnCgpjbGFzcyBDIHsKICBpbml0KCk6IHZvaWQgewogICAgaWYgKCFkZWJ1ZykgcmV0dXJuCiAgICBpZiAoZGVidWcpIGEoKQogICAgYigpCiAgfQp9CgpuZXcgQygpAABmaWxlLnRzAGV4cG9ydCBmdW5jdGlvbiBhKCk6IHZvaWQgewogIGNvbnNvbGUubG9nKCdhJykKfQoKZXhwb3J0IGZ1bmN0aW9uIGIoKTogdm9pZCB7CiAgY29uc29sZS5sb2coJ2InKQp9)

Start by running the provided esbuild command with entry.ts and file.ts, then compare the class-method case with the standalone init function in the examples. The fix is done when the class-method case tree-shakes the unused imports and produces the expected output without the unused function.

Written by the indexing model from the issue text.