bpf, selftests: Adjust few selftest result_unpriv outcomes

Given we don't need to simulate the speculative domain for registers with
immediates anymore since the verifier uses direct imm-based rewrites instead
of having to mask, we can also lift a few cases that were previously rejected.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/verifier/stack_ptr.c

@@ -295,8 +295,6 @@
 	BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1, 0),
 	BPF_EXIT_INSN(),
 	},
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "invalid write to stack R1 off=0 size=1",
 	.result = ACCEPT,
 	.retval = 42,
 },

tools/testing/selftests/bpf/verifier/value_ptr_arith.c

@@ -300,8 +300,6 @@
 	},
 	.fixup_map_array_48b = { 3 },
 	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R0 pointer arithmetic of map value goes out of range",
 	.retval = 1,
 },
 {
@@ -371,8 +369,6 @@
 	},
 	.fixup_map_array_48b = { 3 },
 	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R0 pointer arithmetic of map value goes out of range",
 	.retval = 1,
 },
 {
@@ -472,8 +468,6 @@
 	},
 	.fixup_map_array_48b = { 3 },
 	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R0 pointer arithmetic of map value goes out of range",
 	.retval = 1,
 },
 {
@@ -766,8 +760,6 @@
 	},
 	.fixup_map_array_48b = { 3 },
 	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R0 pointer arithmetic of map value goes out of range",
 	.retval = 1,
 },
 {