Rename EXPERIMENTAL_USE_OPENJDK9 to EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9.

The current EXPERIMENTAL_USE_OPENJDK9 environment variable is a legacy
from when the 8 -> 9 toolchain upgrade was happening. That migration
is done and the variable only affects the language level, so it should
have a name that reflects that. (The current situation would be
especially confusing if we started a 9 -> 11 toolchain upgrade,
presumably controlled by a variable like EXPERIMENTAL_USE_OPENJDK11,
since the two settings look incompatible but are actually orthogonal.)

The current variable historically allowed a value or "1.8" which meant
"use the OpenJDK 9 toolchain but target language level 8". That value
no longer has any meaning and the new variable doesn't allow it.

Bug: 131678633
Test: `make` with `EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9=true`
Test: `javap -v $OUT_DIR/soong/.intermediates/libcore/core-oj/android_common/javac/classes/java/util/List.class | grep 'major version'` shows 53
Test: Audit all mentions of the old string here and downstream
Change-Id: Idad808c7f07913baba1a777627322d5452dabcef

1 files changed, 5 insertions, 5 deletions

diff --git a/java/sdk_test.go b/java/sdk_test.go
index e446129a5..cc4da2eca 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -272,8 +272,8 @@ func TestClasspath(t *testing.T) {
 				}
 			}
 
-			t.Run("1.8", func(t *testing.T) {
-				// Test default javac 1.8
+			t.Run("Java language level 8", func(t *testing.T) {
+				// Test default javac -source 1.8 -target 1.8
 				config := testConfig(nil)
 				if testcase.unbundled {
 					config.TestProductVariables.Unbundled_build = proptools.BoolPtr(true)
@@ -299,9 +299,9 @@ func TestClasspath(t *testing.T) {
 				}
 			})
 
-			// Test again with javac 1.9
-			t.Run("1.9", func(t *testing.T) {
-				config := testConfig(map[string]string{"EXPERIMENTAL_USE_OPENJDK9": "true"})
+			// Test again with javac -source 9 -target 9
+			t.Run("Java language level 9", func(t *testing.T) {
+				config := testConfig(map[string]string{"EXPERIMENTAL_JAVA_LANGUAGE_LEVEL_9": "true"})
 				if testcase.unbundled {
 					config.TestProductVariables.Unbundled_build = proptools.BoolPtr(true)
 				}