Create AnalysisFailureInfo for in-build failure testing.

This new object is tied to a new semantic flag, --experimental_analysis_testing_improvements

Progress toward #6237.

RELNOTES: None.
PiperOrigin-RevId: 215265415

src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
index fb1d2df..90192b7 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
@@ -35,6 +35,8 @@
 
   /** Enum where each element represents a skylark semantics flag. */
   public enum FlagIdentifier {
+    EXPERIMENTAL_ANALYSIS_TESTING_IMPROVEMENTS(
+        SkylarkSemantics::experimentalAnalysisTestingImprovements),
     INCOMPATIBLE_DISABLE_OBJC_PROVIDER_RESOURCES(
         SkylarkSemantics::incompatibleDisableObjcProviderResources),
     INCOMPATIBLE_NO_TARGET_OUTPUT_GROUP(
@@ -89,6 +91,8 @@
       AutoValue_SkylarkSemantics.class;
 
   // <== Add new options here in alphabetic order ==>
+  public abstract boolean experimentalAnalysisTestingImprovements();
+
   public abstract List<String> experimentalCcSkylarkApiEnabledPackages();
 
   public abstract boolean experimentalEnableRepoMapping();
@@ -162,6 +166,7 @@
   public static final SkylarkSemantics DEFAULT_SEMANTICS =
       builder()
           // <== Add new options here in alphabetic order ==>
+          .experimentalAnalysisTestingImprovements(false)
           .experimentalCcSkylarkApiEnabledPackages(ImmutableList.of())
           .experimentalEnableRepoMapping(false)
           .experimentalRemapMainRepo(false)
@@ -198,6 +203,8 @@
   public abstract static class Builder {
 
     // <== Add new options here in alphabetic order ==>
+    public abstract Builder experimentalAnalysisTestingImprovements(boolean value);
+
     public abstract Builder experimentalCcSkylarkApiEnabledPackages(List<String> value);
 
     public abstract Builder experimentalEnableRepoMapping(boolean value);