Precompile python sources

This signifigantly improves the startup time of soong-built
python binaries. For example, running
`m apexer && time out/host/linux-x86/bin/apexer` gives
0.734s before this cl, and 0.094s after.

Fixes: 259718110
Test: Presubmits
Change-Id: Ib19e83e2c60c39a849525be117279c318de3afa7

python/python_test.go

@@ -18,10 +18,10 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"regexp"
 	"testing"
 
 	"android/soong/android"
+	"android/soong/cc"
 )
 
 type pyModule struct {
@@ -33,8 +33,10 @@ type pyModule struct {
 }
 
 var (
-	buildNamePrefix          = "soong_python_test"
-	moduleVariantErrTemplate = "%s: module %q variant %q: "
+	buildNamePrefix = "soong_python_test"
+	// We allow maching almost anything before the actual variant so that the os/arch variant
+	// is matched.
+	moduleVariantErrTemplate = `%s: module %q variant "[a-zA-Z0-9_]*%s": `
 	pkgPathErrTemplate       = moduleVariantErrTemplate +
 		"pkg_path: %q must be a relative path contained in par file."
 	badIdentifierErrTemplate = moduleVariantErrTemplate +
@@ -323,17 +325,26 @@ func TestPythonModule(t *testing.T) {
 		if d.desc != "module with duplicate runfile path" {
 			continue
 		}
-		errorPatterns := make([]string, len(d.errors))
-		for i, s := range d.errors {
-			errorPatterns[i] = regexp.QuoteMeta(s)
-		}
+		d.mockFiles[filepath.Join("common", bpFile)] = []byte(`
+python_library {
+  name: "py3-stdlib",
+  host_supported: true,
+}
+cc_binary {
+  name: "py3-launcher",
+  host_supported: true,
+}
+`)
 
 		t.Run(d.desc, func(t *testing.T) {
 			result := android.GroupFixturePreparers(
 				android.PrepareForTestWithDefaults,
+				android.PrepareForTestWithArchMutator,
+				android.PrepareForTestWithAllowMissingDependencies,
+				cc.PrepareForTestWithCcDefaultModules,
 				PrepareForTestWithPythonBuildComponents,
 				d.mockFiles.AddToFixture(),
-			).ExtendWithErrorHandler(android.FixtureExpectsAllErrorsToMatchAPattern(errorPatterns)).
+			).ExtendWithErrorHandler(android.FixtureExpectsAllErrorsToMatchAPattern(d.errors)).
 				RunTest(t)
 
 			if len(result.Errs) > 0 {