[TableGen] Avoid warnings with INT64_MIN

The number 0x8000000000000000 caused:

    warning: integer constant is so large that it is unsigned

Emit the INT64_MIN macro instead of a negative literal.

Triggered in #151687

Author: pfusik

llvm/test/TableGen/GlobalISelEmitter/int64min.td

@@ -17,12 +17,12 @@ def ANDI : I<(outs GPR:$dst), (ins GPR:$src1, i64imm:$src2), []>;
 // CHECK-NEXT: GIM_RootCheckRegBankForClass, /*Op*/1, /*RC*/GIMT_Encode2(MyTarget::GPRRegClassID),
 // CHECK-NEXT: // MIs[0] Operand 2
 // CHECK-NEXT: GIM_RootCheckType, /*Op*/2, /*Type*/GILLT_s64,
-// CHECK-NEXT: GIM_CheckConstantInt, /*MI*/0, /*Op*/2, GIMT_Encode8(-9223372036854775808),
+// CHECK-NEXT: GIM_CheckConstantInt, /*MI*/0, /*Op*/2, GIMT_Encode8(INT64_MIN),
 // CHECK-NEXT: // (and:{ *:[i64] } GPR:{ *:[i64] }:$rs1, -9223372036854775808:{ *:[i64] })  =>  (ANDI:{ *:[i64] } GPR:{ *:[i64] }:$rs1, -9223372036854775808:{ *:[i64] })
 // CHECK-NEXT: GIR_BuildRootMI, /*Opcode*/GIMT_Encode2(MyTarget::ANDI),
 // CHECK-NEXT: GIR_RootToRootCopy, /*OpIdx*/0, // DstI[dst]
 // CHECK-NEXT: GIR_RootToRootCopy, /*OpIdx*/1, // rs1
-// CHECK-NEXT: GIR_AddImm, /*InsnID*/0, /*Imm*/GIMT_Encode8(-9223372036854775808),
+// CHECK-NEXT: GIR_AddImm, /*InsnID*/0, /*Imm*/GIMT_Encode8(INT64_MIN),
 // CHECK-NEXT: GIR_RootConstrainSelectedInstOperands,
 // CHECK-NEXT: // GIR_Coverage, 0,
 // CHECK-NEXT: GIR_EraseRootFromParent_Done,

llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.cpp

@@ -237,7 +237,7 @@ MatchTableRecord MatchTable::NamedValue(unsigned NumBytes, StringRef Namespace,
 
 MatchTableRecord MatchTable::IntValue(unsigned NumBytes, int64_t IntValue) {
   assert(isUIntN(NumBytes * 8, IntValue) || isIntN(NumBytes * 8, IntValue));
-  auto Str = llvm::to_string(IntValue);
+  auto Str = IntValue == INT64_MIN ? "INT64_MIN" : llvm::to_string(IntValue);
   if (NumBytes == 1 && IntValue < 0)
     Str = "uint8_t(" + Str + ")";
   // TODO: Could optimize this directly to save the compiler some work when