[libc] Fix forward octal prefix (#73526)

To fix failing build bots after :
#73372

```
/home/libc-buildbot/libc-aarch64-ubuntu/libc-aarch64-ubuntu-fullbuild-dbg/llvm-project/libc/src/__support/macros/properties/float.h:40:71: error: invalid digit '9' in octal constant
#if (defined(LIBC_COMPILER_CLANG_VER) && (LIBC_COMPILER_CLANG_VER >= 0900)) || \
```

Author: gchatelet

libc/src/__support/macros/properties/float.h

@@ -37,7 +37,7 @@
 #endif
 #endif
 #if defined(LIBC_TARGET_ARCH_IS_AARCH64)
-#if (defined(LIBC_COMPILER_CLANG_VER) && (LIBC_COMPILER_CLANG_VER >= 0900)) || \
+#if (defined(LIBC_COMPILER_CLANG_VER) && (LIBC_COMPILER_CLANG_VER >= 900)) ||  \
     (defined(LIBC_COMPILER_GCC_VER) && (LIBC_COMPILER_GCC_VER >= 1301))
 #define LIBC_COMPILER_HAS_C23_FLOAT16
 #endif
@@ -61,7 +61,7 @@ using float16 = _Float16;
      defined(LIBC_TARGET_ARCH_IS_X86_64))
 #define LIBC_COMPILER_HAS_C23_FLOAT128
 #endif
-#if (defined(LIBC_COMPILER_CLANG_VER) && (LIBC_COMPILER_CLANG_VER >= 0500)) && \
+#if (defined(LIBC_COMPILER_CLANG_VER) && (LIBC_COMPILER_CLANG_VER >= 500)) &&  \
     (defined(LIBC_TARGET_ARCH_IS_X86_64))
 #define LIBC_COMPILER_HAS_FLOAT128_EXTENSION
 #endif