Refactor the test runner

Changes

- Support multi-threaded testing.
- Support `set_fail_timeout` on all platforms.
- Display an animated progress report.
- Setup all tests with a context logger.
- Give all tests their own separate custom allocators.
- Support tracking test memory usage.
- Display a summary of the failed tests at the end.
- Let users select only specific tests to run.
- Support copying failed tests to the clipboard to run again.
- Support catching SIGINT (CTRL-C) to cancel early.
- Record context in cleanup procs.
- Write all log messages to STDERR for easy redirection.
- Possibly more I've forgotten.

New Options

- `-define:test_threads=N`: Specify thread count.
- `-define:test_thread_memory=B`: Specify initial memory block size in bytes to each thread.
- `-define:test_track_memory=true`: Track the memory usage of individual tests.
- `-define:test_fancy=false`: Disable animated progress report.
- `-define:test_select=package.test_name,...`: Run only select tests.
- `-define:test_clipboard=true`: Copy names of failed tests to the clipboard.
- `-define:test_progress_width=24`: Change the width of the animated progress bars.

core/testing/logging.odin

@@ -0,0 +1,71 @@
+//+private
+package testing
+
+import "base:runtime"
+import "core:fmt"
+import pkg_log "core:log"
+import "core:strings"
+import "core:sync/chan"
+import "core:time"
+
+Default_Test_Logger_Opts :: runtime.Logger_Options {
+	.Level,
+	.Terminal_Color,
+	.Short_File_Path,
+	.Line,
+	.Procedure,
+	.Date, .Time,
+}
+
+Log_Message :: struct {
+	level: runtime.Logger_Level,
+	text: string,
+	time: time.Time,
+	// `text` may be allocated differently, depending on where a log message
+	// originates from.
+	allocator: runtime.Allocator,
+}
+
+test_logger_proc :: proc(logger_data: rawptr, level: runtime.Logger_Level, text: string, options: runtime.Logger_Options, location := #caller_location) {
+	t := cast(^T)logger_data
+
+	if level >= .Error {
+		t.error_count += 1
+	}
+
+	cloned_text, clone_error := strings.clone(text, t._log_allocator)
+	assert(clone_error == nil, "Error while cloning string in test thread logger proc.")
+
+	now := time.now()
+
+	chan.send(t.channel, Event_Log_Message {
+		level = level,
+		text = cloned_text,
+		time = now,
+		formatted_text = format_log_text(level, text, options, location, now, t._log_allocator),
+	})
+}
+
+runner_logger_proc :: proc(logger_data: rawptr, level: runtime.Logger_Level, text: string, options: runtime.Logger_Options, location := #caller_location) {
+	log_messages := cast(^[dynamic]Log_Message)logger_data
+
+	now := time.now()
+
+	append(log_messages, Log_Message {
+		level = level,
+		text = format_log_text(level, text, options, location, now),
+		time = now,
+		allocator = context.allocator,
+	})
+}
+
+format_log_text :: proc(level: runtime.Logger_Level, text: string, options: runtime.Logger_Options, location: runtime.Source_Code_Location, at_time: time.Time, allocator := context.allocator) -> string{
+	backing: [1024]byte
+	buf := strings.builder_from_bytes(backing[:])
+
+	pkg_log.do_level_header(options, &buf, level)
+	pkg_log.do_time_header(options, &buf, at_time)
+	pkg_log.do_location_header(options, &buf, location)
+
+	return fmt.aprintf("%s%s", strings.to_string(buf), text, allocator = allocator)
+}