Revert "Mark lambda main methods as synthetic."

This reverts commit bd1ec4e2a3e43cd35a1564d2dbda91e11b959c44.
Bug: b/171599229

Change-Id: Ieb4f2f3658267dff36344618fa07df8f15bc41d2

src/main/java/com/android/tools/r8/ir/desugar/LambdaClass.java

diff --git a/src/main/java/com/android/tools/r8/ir/desugar/LambdaClass.java b/src/main/java/com/android/tools/r8/ir/desugar/LambdaClass.java
index 9b8f930..c9e47c2 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/LambdaClass.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/LambdaClass.java
@@ -233,7 +233,7 @@
         new DexEncodedMethod(
             mainMethod,
             MethodAccessFlags.fromSharedAccessFlags(
-                Constants.ACC_PUBLIC | Constants.ACC_FINAL | Constants.ACC_SYNTHETIC, false),
+                Constants.ACC_PUBLIC | Constants.ACC_FINAL, false),
             MethodTypeSignature.noSignature(),
             DexAnnotationSet.empty(),
             ParameterAnnotationsList.empty(),

src/test/java/com/android/tools/r8/debug/DebugTestBase.java

diff --git a/src/test/java/com/android/tools/r8/debug/DebugTestBase.java b/src/test/java/com/android/tools/r8/debug/DebugTestBase.java
index 44bcc80..13d59dc 100644
--- a/src/test/java/com/android/tools/r8/debug/DebugTestBase.java
+++ b/src/test/java/com/android/tools/r8/debug/DebugTestBase.java
@@ -2108,6 +2108,14 @@
           }
           return false;
         }
+        if (isInLambdaClass(mirror, location)) {
+          // Lambda classes must be skipped since they are only wrappers around lambda code.
+          if (DEBUG_TESTS) {
+            System.out.println("Skipping lambda class wrapper method");
+          }
+          wrapper.enqueueCommandFirst(stepCommand);
+          return true;
+        }
         if (isSyntheticMethod(mirror, location)) {
           if (DEBUG_TESTS) {
             System.out.println("Skipping synthetic method");
@@ -2152,6 +2160,11 @@
         return false;
       }
 
+      private static boolean isInLambdaClass(VmMirror mirror, Location location) {
+        String classSig = mirror.getClassSignature(location.classID);
+        return classSig.contains("$$Lambda$");
+      }
+
       private static boolean isLambdaMethod(VmMirror mirror, Location location) {
         String methodName = mirror.getMethodName(location.classID, location.methodID);
         return methodName.startsWith("lambda$");