Can't expand macros inside EM_ASM and EM_JS

**Version of emscripten/emsdk:**

```
$ emcc -v
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.3-git (a9651ff57165f5710b
b09a5fe52590fd6ddb72df)
clang version 21.0.0git
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: C:/msys64/clang64/opt/emscripten-llvm/bin
```

**Failing command line in full:**

```
$ cat asm-preprocessor.c
#include

int main(void)
{
#define VAL 'hi'
EM_ASM(console.log(VAL));
return 0;
}
$ emcc asm-preprocessor.c && node a.out.js
D:\Random\C\a.out.js:844
65536: () => { console.log(VAL) }
^

ReferenceError: VAL is not defined
at 65536 (D:\Random\C\a.out.js:844:30)
at runEmAsmFunction (D:\Random\C\a.out.js:970:30)
at _emscripten_asm_const_int (D:\Random\C\a.out.js:973:14)
at wasm://wasm/afa51dde:wasm-function[2]:0x232
at wasm://wasm/afa51dde:wasm-function[3]:0x258
at D:\Random\C\a.out.js:688:12
at callMain (D:\Random\C\a.out.js:1352:15)
at doRun (D:\Random\C\a.out.js:1404:24)
at run (D:\Random\C\a.out.js:1417:5)
at removeRunDependency (D:\Random\C\a.out.js:624:7)

Node.js v23.5.0
```

this is the workaround:

```
$ cat asm-preprocessor-good.c
#include

int main(void)
{
#define VAL 'hi'
#define EM_ASM2(...) EM_ASM(__VA_ARGS__)
EM_ASM2(console.log(VAL));
return 0;
}
$ emcc asm-preprocessor-good.c && node a.out.js
hi
```

I believe users would be surprised if their JavaScript code suddenly started expanding macros after a "fix". hence, I believe it is more useful if every macro of EM_ASM family and EM_JS gets a second version that performs macro expansion before stringification. otherwise, at least document the current behavior in documentation, providing rationale and the workaround.