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

cmd/merge_zips/merge_zips.go

@@ -359,7 +359,8 @@ func (oz *OutputZip) getUninitializedPythonPackages(inputZips []InputZip) ([]str
 		}
 		for _, file := range inputZip.Entries() {
 			pyPkg := getPackage(file.Name)
-			if filepath.Base(file.Name) == "__init__.py" {
+			baseName := filepath.Base(file.Name)
+			if baseName == "__init__.py" || baseName == "__init__.pyc" {
 				if _, found := initedPackages[pyPkg]; found {
 					panic(fmt.Errorf("found __init__.py path duplicates during pars merging: %q", file.Name))
 				}