Remove support for EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9.

Prior to this change, setting that to "false" turned the default Java
language level back to 8. This change removes that option.

Bug: 115604102
Test: m java droid docs tests cts
Change-Id: I97bfd0dc8d941008b4071c6efe1c0c24950c4f1f
diff --git a/java/config/makevars.go b/java/config/makevars.go
index 2fa6f89..981a736 100644
--- a/java/config/makevars.go
+++ b/java/config/makevars.go
@@ -29,12 +29,6 @@
 	ctx.Strict("TARGET_DEFAULT_BOOTCLASSPATH_LIBRARIES", strings.Join(DefaultBootclasspathLibraries, " "))
 	ctx.Strict("DEFAULT_SYSTEM_MODULES", DefaultSystemModules)
 
-	if ctx.Config().TargetOpenJDK9() {
-		ctx.Strict("DEFAULT_JAVA_LANGUAGE_VERSION", "1.9")
-	} else {
-		ctx.Strict("DEFAULT_JAVA_LANGUAGE_VERSION", "1.8")
-	}
-
 	ctx.Strict("ANDROID_JAVA_HOME", "${JavaHome}")
 	ctx.Strict("ANDROID_JAVA8_HOME", "prebuilts/jdk/jdk8/${hostPrebuiltTag}")
 	ctx.Strict("ANDROID_JAVA9_HOME", "prebuilts/jdk/jdk9/${hostPrebuiltTag}")
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 12335ff..1091331 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -425,16 +425,12 @@
 		if sdkDep.hasStandardLibs() {
 			if sdkDep.useDefaultLibs {
 				ctx.AddVariationDependencies(nil, bootClasspathTag, config.DefaultBootclasspathLibraries...)
-				if ctx.Config().TargetOpenJDK9() {
-					ctx.AddVariationDependencies(nil, systemModulesTag, config.DefaultSystemModules)
-				}
+				ctx.AddVariationDependencies(nil, systemModulesTag, config.DefaultSystemModules)
 				if sdkDep.hasFrameworkLibs() {
 					ctx.AddVariationDependencies(nil, libTag, config.DefaultLibraries...)
 				}
 			} else if sdkDep.useModule {
-				if ctx.Config().TargetOpenJDK9() {
-					ctx.AddVariationDependencies(nil, systemModulesTag, sdkDep.systemModules)
-				}
+				ctx.AddVariationDependencies(nil, systemModulesTag, sdkDep.systemModules)
 				ctx.AddVariationDependencies(nil, bootClasspathTag, sdkDep.modules...)
 			}
 		} else if sdkDep.systemModules != "" {
diff --git a/java/java.go b/java/java.go
index be48256..71d0098 100644
--- a/java/java.go
+++ b/java/java.go
@@ -884,7 +884,7 @@
 		ret = normalizeJavaVersion(ctx, javaVersion)
 	} else if ctx.Device() && sdk <= 23 {
 		ret = "1.7"
-	} else if ctx.Device() && sdk <= 29 || !ctx.Config().TargetOpenJDK9() {
+	} else if ctx.Device() && sdk <= 29 {
 		ret = "1.8"
 	} else if ctx.Device() &&
 		sdkContext.sdkVersion() != "" &&