Bazel: fallback to default absolute path logic (#620)

* Remove unnecessary throw for unexpected exception

* Bazel: fallback to default absolute path logic

Previously, we failed compilation when failing to infer the absolute
path of a file that was being compiled by Bazel. This commit changes the
behavior to fallback to the default behavior, which uses the standard
`JavaFileObject.toUri()` API. The goal of this change is to fix an issue
that happened when using errorprone together with semanticdb-javac, and
errorprone triggers compilation with custom compilation unit here

https://sourcegraph.com/github.com/google/error-prone@77ba705df2c213eddd5652622336f4a8fef3c387/-/blob/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java

Author: olafurpg

semanticdb-javac/src/main/java/com/sourcegraph/semanticdb_javac/SemanticdbTaskListener.java

@@ -146,10 +146,10 @@ public static Path absolutePathFromUri(SemanticdbJavacOptions options, JavaFileO
           return options.sourceroot.resolve(path);
         }
       }
-      throw new IllegalArgumentException("unsupported source file: " + toString);
-    } else {
-      return Paths.get(uri);
+      // Fallback to default behavior.
     }
+
+    return Paths.get(uri);
   }
 
   // Infers the `-sourceroot:` flag from the provided file.