[clang][Interp][NFC] Make a test array smaller

The large size doesn't add anything here, at least not with the
test in its current form.

Author: tbaederr

clang/test/AST/Interp/arrays.cpp

@@ -562,10 +562,10 @@ namespace LocalVLA {
   }
 }
 
-char melchizedek[2200000000];
+char melchizedek[2];
 typedef decltype(melchizedek[1] - melchizedek[0]) ptrdiff_t;
-constexpr ptrdiff_t d1 = &melchizedek[0x7fffffff] - &melchizedek[0]; // ok
-constexpr ptrdiff_t d3 = &melchizedek[0] - &melchizedek[0x80000000u]; // ok
+constexpr ptrdiff_t d1 = &melchizedek[1] - &melchizedek[0]; // ok
+constexpr ptrdiff_t d3 = &melchizedek[0] - &melchizedek[1]; // ok
 
 /// GH#88018
 const int SZA[] = {};