8316907: Fix nonnull-compare warnings

Backport-of: 516cfb135f7e5fefaf6e6f2928f6ecb88806f1ef

Author: SendaoYan

src/hotspot/share/adlc/output_c.cpp

@@ -726,7 +726,6 @@ void ArchDesc::build_pipe_classes(FILE *fp_cpp) {
   fprintf(fp_cpp, "  }\n");
   fprintf(fp_cpp, "#endif\n\n");
 #endif
-  fprintf(fp_cpp, "  assert(this, \"null pipeline info\");\n");
   fprintf(fp_cpp, "  assert(pred, \"null predecessor pipline info\");\n\n");
   fprintf(fp_cpp, "  if (pred->hasFixedLatency())\n    return (pred->fixedLatency());\n\n");
   fprintf(fp_cpp, "  // If this is not an operand, then assume a dependence with 0 latency\n");

src/hotspot/share/asm/codeBuffer.cpp

@@ -1059,11 +1059,6 @@ void CodeSection::print(const char* name) {
 }
 
 void CodeBuffer::print() {
-  if (this == nullptr) {
-    tty->print_cr("null CodeBuffer pointer");
-    return;
-  }
-
   tty->print_cr("CodeBuffer:");
   for (int n = 0; n < (int)SECT_LIMIT; n++) {
     // print each section