Use test ([) instead of extended test ([[) in if statements

- Using extended test is not portable since some /bin/sh doesn't support it.

[  4% 5228/128453 3h38m43s remaining] //external/javaparser:javaparser javac [linux_glibc common]
/bin/sh: 1: [[: not found

- Use "test" instead

Change-Id: Ic29eb8cd04b8d29b4b8ca8863a826b073c2d2d71
diff --git a/java/kotlin.go b/java/kotlin.go
index e1a3f71..308bb03 100644
--- a/java/kotlin.go
+++ b/java/kotlin.go
@@ -198,7 +198,7 @@
 			`$kaptProcessor ` +
 			`-Xbuild-file=$kotlinBuildFile && ` +
 			`${config.SoongZipCmd} -jar -write_if_changed -o $out -C $kaptDir/stubs -D $kaptDir/stubs && ` +
-			`if [[ -f "$out.pc_state.new" ]]; then mv "$out.pc_state.new" "$out.pc_state"; fi && ` +
+			`if [ -f "$out.pc_state.new" ]; then mv "$out.pc_state.new" "$out.pc_state"; fi && ` +
 			`rm -rf "$srcJarDir"`,
 		CommandDeps: []string{
 			"${config.FindInputDeltaCmd}",