Propagate LANG environment variable to lint in RBE

Without LANG, lint's text output is ASCII instead of UTF-8, causing
differences between local and remote execution.

Bug: 181681346
Bug: 182415460
Test: m USE_RBE=true RBE_LINT=true
Change-Id: I0ad54aa731582c9b54abb80f50ba508c75992b91

java/lint.go

@@ -422,6 +422,7 @@ func (l *linter) lint(ctx android.ModuleContext) {
 				"ANDROID_SDK_HOME",
 				"SDK_ANNOTATIONS",
 				"LINT_OPTS",
+				"LANG",
 			},
 			Platform: map[string]string{remoteexec.PoolKey: pool},
 		}).NoVarTemplate(ctx.Config()))