[scudo] Use stdint types for internal scudo types

`scudo::uptr` was defined as an `unsigned long` on 32-b platform,
while a `uintptr_t` is usually defined as an `unsigned int`.
This worked, this was not consistent, particularly with regard to
format string specifiers.

As suggested by Vitaly, since we are including `stdint.h`, define
the internal `scudo` integer types to those.

Differential Revision: https://reviews.llvm.org/D108089

compiler-rt/lib/scudo/standalone/internal_defs.h

@@ -78,16 +78,16 @@
 
 namespace scudo {
 
-typedef unsigned long uptr;
-typedef unsigned char u8;
-typedef unsigned short u16;
-typedef unsigned int u32;
-typedef unsigned long long u64;
-typedef signed long sptr;
-typedef signed char s8;
-typedef signed short s16;
-typedef signed int s32;
-typedef signed long long s64;
+typedef uintptr_t uptr;
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+typedef intptr_t sptr;
+typedef int8_t s8;
+typedef int16_t s16;
+typedef int32_t s32;
+typedef int64_t s64;
 
 // The following two functions have platform specific implementations.
 void outputRaw(const char *Buffer);