Emit brk #0xf000 for breakpoint opcode on arm64 (#267)

Implement SLJIT_BREAKPOINT with the same instruction emitted by MSVC for
the __debugbreak intrinsic (brk #0xf000) and by Clang for
__builtin_debugtrap. On Windows, this triggers a breakpoint exception
just as int3 does on x86. The previously emitted instruction (brk #0)
triggers an illegal instruction exception instead.

LLDB also has special handling for this brk variant on Windows and
macOS, automatically advancing to the next instruction so execution can
be easily continued.

sljit_src/sljitNativeARM_64.c

@@ -1548,7 +1548,7 @@ SLJIT_API_FUNC_ATTRIBUTE sljit_s32 sljit_emit_op0(struct sljit_compiler *compile
 	op = GET_OPCODE(op);
 	switch (op) {
 	case SLJIT_BREAKPOINT:
-		return push_inst(compiler, BRK);
+		return push_inst(compiler, BRK | (0xf000 << 5));
 	case SLJIT_NOP:
 		return push_inst(compiler, NOP);
 	case SLJIT_LMUL_UW: