Add tests for new test failure expectation API

tests/core/testing/test_core_testing.odin

@@ -0,0 +1,52 @@
+package test_core_testing
+
+import "core:c/libc"
+import "core:math/rand"
+import "core:testing"
+
+@test
+test_expected_assert :: proc(t: ^testing.T) {
+	target := #location(); target.line += 2; target.column = 2
+	testing.expect_assert_from(t, target)
+	assert(false)
+}
+
+@test
+test_expected_two_assert :: proc(t: ^testing.T) {
+	target1 := #location(); target1.line += 5; target1.column = 3
+	target2 := #location(); target2.line += 6; target2.column = 3
+	testing.expect_assert_from(t, target1)
+	testing.expect_assert_from(t, target2)
+	if rand.uint32() & 1 == 0 {
+		assert(false)
+	} else {
+		assert(false)
+	}
+}
+
+some_proc :: proc() {
+	assert(false)
+}
+
+@test
+test_expected_assert_in_proc :: proc(t: ^testing.T) {
+	target := #location(some_proc)
+	target.line += 1
+	target.column = 2
+	assert(target.procedure == "", "The bug's been fixed; this line and the next can be deleted.")
+	target.procedure = "some_proc" // TODO: Is this supposed to be blank on #location(...)?
+	testing.expect_assert(t, target)
+	some_proc()
+}
+
+@test
+test_expected_assert_message :: proc(t: ^testing.T) {
+	testing.expect_assert(t, "failure")
+	assert(false, "failure")
+}
+
+@test
+test_expected_signal :: proc(t: ^testing.T) {
+	testing.expect_signal(t, libc.SIGILL)
+	libc.raise(libc.SIGILL)
+}