Add -XDshould-stop.ifError=FLOW to the default javacopts.

See google/error-prone#4595 for motivation. This fixes a bug with the interaction between javac and Error Prone, but also improves diagnostic quality in general by showing more errors if there are multiple problems and multiple files being compiled.

PiperOrigin-RevId: 686100365
Change-Id: I2e5e6dffdbbe1ca6480369a51a7ea3445db78a8a

toolchains/default_java_toolchain.bzl

@@ -56,6 +56,7 @@ JDK9_JVM_OPTS = BASE_JDK9_JVM_OPTS
 DEFAULT_JAVACOPTS = [
     "-XDskipDuplicateBridges=true",
     "-XDcompilePolicy=simple",
+    "-XDshould-stop.ifError=FLOW",  # See b/27049950, https://github.com/google/error-prone/issues/4595
     "-g",
     "-parameters",
     # https://github.com/bazelbuild/bazel/issues/15219