[NFC][clang] Correct bswapg test to work when int128 is not available

This updates the test to avoid inclusion of int128 bswapg tests on targets
that don't support int128 at all.

This fixes failures introduced by #162433

Author: ojhunt

clang/test/CodeGen/builtins.c

@@ -1289,7 +1289,10 @@ void test_builtin_ctzg(unsigned char uc, unsigned short us, unsigned int ui,
 // CHECK-LABEL: define{{.*}} void @test_builtin_bswapg
 void test_builtin_bswapg(unsigned char uc, unsigned short us, unsigned int ui,
                        unsigned long ul, unsigned long long ull,
-                       unsigned __int128 ui128, _BitInt(8) bi8,
+#ifdef __SIZEOF_INT128__
+                       unsigned __int128 ui128,
+#endif
+                       _BitInt(8) bi8,
                        _BitInt(16) bi16, _BitInt(32) bi32, 
                        _BitInt(64) bi64, _BitInt(128) bi128) {
   uc = __builtin_bswapg(uc);
@@ -1303,8 +1306,10 @@ void test_builtin_bswapg(unsigned char uc, unsigned short us, unsigned int ui,
   // CHECK: call i64 @llvm.bswap.i64
   ull = __builtin_bswapg(ull);
   // CHECK: call i64 @llvm.bswap.i64
+#ifdef __SIZEOF_INT128__
   ui128 = __builtin_bswapg(ui128);
   // CHECK: call i128 @llvm.bswap.i128
+#endif
   bi8 = __builtin_bswapg(bi8);
   // CHECK: %17 = load i8, ptr %bi8.addr, align 1
   // CHECK: store i8 %17, ptr %bi8.addr