[Compiler Bug]: Functions defined in render that return primitives don't have usages memoized

### What kind of issue is this? - [x] React Compiler core (the JS output is incorrect, or your app works incorrectly after optimization) - [ ] babel-plugin-react-compiler (build issue installing or using the Babel plugin) - [ ] eslint-plugin-react-compiler (build issue installing or using the eslint plugin) - [ ] react-compiler-healthcheck (build issue installing or using the healthcheck script) ### Link to repro https://playground.react.dev/#N4Igzg9grgTgxgUxALhASwLYAcIwC4AEwBUYCAyngIZ4IEC+BAZjBBgQOQwJVx4cBuADoA7UUygi+aCCIIAhKgBMAFAEoioggTiywhANq7JtGABoCZPAGFoI0wF0CAXhJlKNBCoAMa4WLlmSWlZAgQADywEETA0ADcEW2woajwZEXVNQO0mXAIVABsEQjQXAm8BAlKAHgIATga6yrQAahaNYC1tBi7tbjxYOQBmf216US6AekmCJKwUhCUw3gALAm4RJQQYAEIu3RjCCKiY+IQANSoCqDpXY+jYhLmUmnT1fy7+wYJqgCMUvChWTWApoOAAa2cwEyzgAfJZirYTNsVHI4QQ5C0CABGNT0WFI+zIIjGezbRjAe6nBKXa4IejVSb-PCAkSw0TjAISKRpUIAcQgEFUHX2ekMpNMFishMcZVIFFSXl8H0C3JCcipj0SbHmqTeIuyzDyhWKVTKFTNtUaTSqbQN3R6hq+MDkxDiVxuxKGDFGjqmMwAchBCLpkrQljw4GsNltdqLDmFIg8zrSbmVNWdnnrZO8JoFnXI-gCgSIQWDIdCNOjpXZTKiXPDMTi8QTa8TgBLyUQMzSPQgAHTuukMpnFtkcvNq3lyACCBUgAqFmU6gQO+gIRlr2yliK3MCcrnlHloPj8ee00wIQZDOoWEdW62isb2q7FiZOWtTt3fyaet+zGRngEfTFN8RYsiWZYQlCMLwjWyIwPW6JNri+Iyu2nYwBSPYXH2I7Mqy7IiJy4jBNOP7UtqYavDm9pGjA+RFCU5rND89SNM0dpZGMnygS6BAjByID0EAA ### Repro steps Loving the compiler so far! Here's a bit of an inconsistency I've discovered - apologies if it's been brought up elsewhere. If a function: - is defined in the body of a component - returns a primitive value, instead of an object calls to it won't be memoized, even if it's particularly expensive. Here's an example of what I mean: `expensiveComputation` is called every render (i.e. every time the button is clicked). ```jsx function Bad() { const [counter, setCounter] = useState(0); function expensiveComputation() { for (let i = 0; i < 9999; i++) { } return 3; } // Computed each render! const expensiveValue = expensiveComputation(); return <button onClick={() => setCounter(n => n + 1)}>Count: {co…