[compiler-rt] [scudo] Add a method to use a hard-coded page size (PR #106646)

[via llvm-commits]

================
@@ -12,13 +12,19 @@
 
 namespace scudo {
 
-uptr PageSizeCached;
+#if !defined(SCUDO_PAGE_SIZE)
----------------
ChiaHungDuan wrote:

Not sure if there's the function ordering issue here. Can we group the cases of SCUDO_PAGE_SIZE together like
```
#if defined(SCUDO_PAGE_SIZE)
...
#else
...
#endif
```

https://github.com/llvm/llvm-project/pull/106646