JIT/AArch64: Fix an undefined symbol issue (#12687)

In AArch64 function `zend_jit_set_veneer()`, some debug code calls two
other functions `ir_disasm_find_symbol()` and `ir_disasm_add_symbol()`
defined in `ir_disasm.c`. However, `ir_disasm.c` is compiled under the
condition that capstone is available. This causes an undefined symbol
issue while loading `opcache.so` when JIT is triggered if PHP is built
without `--with-capstone`.

We find this issue on MacOS 12.5 if we build PHP with Clang 14. It does
not appear immediately when using other versions of toolchains because
of lazy binding. To reproduce this with Linux/GCC, we can disable lazy
binding by `export LD_BIND_NOW=1` before building PHP.

This fixes the issue by making the debug code conditionally compile.

Author: pfustc

ext/opcache/jit/zend_jit_ir.c

@@ -384,6 +384,7 @@ static bool zend_jit_set_veneer(ir_ctx *ctx, const void *addr, const void *venee
 		if (zend_jit_stub_handlers[i] == addr) {
 			const void **ptr = (const void**)&zend_jit_stub_handlers[count + i];
 			*ptr = veneer;
+#ifdef HAVE_CAPSTONE
 		    if (JIT_G(debug) & ZEND_JIT_DEBUG_ASM) {
 				const char *name = ir_disasm_find_symbol((uint64_t)(uintptr_t)addr, &offset);
 
@@ -399,6 +400,7 @@ static bool zend_jit_set_veneer(ir_ctx *ctx, const void *addr, const void *venee
 					}
 				}
 			}
+#endif
 			return 1;
 		}
 	}