tools/test-all.sh: Reimplement in golang

Makes future development easier.

New features:
* A more compact and cleaner results view
* Concurrent testing, much quicker across multiple cores
* Supports comparing output against an expected file, including a text diff of differences. Also has a flag for updating the expected outputs
* Advanced file-globbing support, including scanning for files in subdirectories
* Skip lists are now no longer hidden away in the tool, but defined as a SKIP header in the *.expected.* file

Change-Id: I4fac80bb084a720ec9a307b4acf9f73792973a1d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/50903
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>

tools/src/glob/glob.go

@@ -22,6 +22,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"dawn.googlesource.com/tint/tools/src/match"
 )
@@ -92,7 +93,12 @@ func LoadConfig(path string) (Config, error) {
 	if err != nil {
 		return Config{}, err
 	}
-	d := json.NewDecoder(bytes.NewReader(cfgBody))
+	return ParseConfig(string(cfgBody))
+}
+
+// ParseConfig parses the config from a JSON string.
+func ParseConfig(config string) (Config, error) {
+	d := json.NewDecoder(strings.NewReader(config))
 	cfg := Config{}
 	if err := d.Decode(&cfg); err != nil {
 		return Config{}, err
@@ -100,6 +106,17 @@ func LoadConfig(path string) (Config, error) {
 	return cfg, nil
 }
 
+// MustParseConfig parses the config from a JSON string, panicing if the config
+// does not parse
+func MustParseConfig(config string) Config {
+	d := json.NewDecoder(strings.NewReader(config))
+	cfg := Config{}
+	if err := d.Decode(&cfg); err != nil {
+		panic(fmt.Errorf("Failed to parse config: %w\nConfig:\n%v", err, config))
+	}
+	return cfg
+}
+
 // rule is a search path predicate.
 // root is the project relative path.
 // cond is the value to return if the rule doesn't either include or exclude.