[prof] remove wrong cast for format string (#18477)
[prof] remove wrong cast for format string
Fixes this warning:
```
CC mprof-report.o
mprof-report.c:408:62: warning: format specifies type 'char *' but the argument has type 'guint64' (aka 'unsigned long long') [-Wformat]
snprintf (format, sizeof (format), "%s : %%" PRIu64 "\n", (guint64)key_format);
~~ ^~~~~~~~~~~~~~~~~~~
%llu
/Applications/Xcode112.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/secure/_stdio.h:57:62: note: expanded from macro
'snprintf'
__builtin___snprintf_chk (str, len, 0, __darwin_obsz(str), __VA_ARGS__)
^~~~~~~~~~~
```
mistake in refactoring commit https://github.com/mono/mono/commit/
07402062541fa9555bef99dbaac84cfb587926cd#diff-c825627ea9ddb3fa753fa3617eaec7c8R408