Make Dep Module Monomorphization Use Hermetic Java Toolchain

Previously the subprocesses were getting triggered via a direct call to `java -jar ...`
which I've only now realized breaks Claro's efforts to make installing Bazel the only
requirement for getting running as you'd also need to have Java installed locally before
you'd be able to run any Claro programs that made use of generic procedures from dep modles.

This update is a bit of a hack to ensure that supbrocesses are started using the hermetic
Java toolchain provided by Bazel via the `common --java_runtime_version=remotejdk_11`
flag configured in the .bazelrc. This should ensure that anyone who simply runs the
`create_claro_project.sh` script will be setup to run Claro programs without any further
setup necessary.

I got lucky to notice this since obviously on my dev machine I already had Java installed.

src/java/com/claro/compiler_backends/java_source/monomorphization/BUILD

@@ -1,5 +1,26 @@
 load("//src/java/com/claro:claro_build_rules_internal.bzl", "bootstrapped_claro_module_internal", "bootstrapped_claro_module", "CLARO_BUILTIN_JAVA_DEPS")
 
+# We need to ensure that users don't need to have Java installed at all. So, this hack ensures hermeticity by ensuring that the 
+# Dep Module Monomorphization subprocesses are invoked using the hermetic Java toolchain, rather than just attempting to directly
+# invoke `java -jar ...`. This is certainly a bit of a hack that relies on some very specific Bazel behavior that risks being
+# changed in later Bazel versions. So, while this helps address a problem with Claro's monomorphization, I still can't wait for
+# subprocesses to no longer be required.
+genrule(
+	name = "get_java_path",
+ 	outs = ["java_path.txt"],
+	cmd = "realpath $(JAVA) > $(OUTS)",
+	toolchains = ["@bazel_tools//tools/jdk:current_java_runtime"],
+)
+
+genrule(
+    name = "monomorphization_coordinator_with_bazel_java",
+    srcs = ["java_path.txt", "MonomorphizationCoordinator.tmpl.java"],
+    outs = ["MonomorphizationCoordinator.java"],
+    cmd = """
+	sed "s#{{BAZEL_JAVA_PATH}}#$$(<$(location java_path.txt))#g" $(location MonomorphizationCoordinator.tmpl.java) > $(OUTS)
+    """
+)
+
 java_library(
     name = "monomorphization_coordinator",
     srcs = ["MonomorphizationCoordinator.java"],
@@ -86,4 +107,4 @@ java_binary(
     visibility = [
         "//src/java/com/claro:__pkg__",
     ]
-)
+)

src/java/com/claro/compiler_backends/java_source/monomorphization/MonomorphizationCoordinator.java → src/java/com/claro/compiler_backends/java_source/monomorphization/MonomorphizationCoordinator.tmpl.java

@@ -181,7 +181,8 @@ private static ListenableFuture<DepModuleMonomorphizationService> getDepModuleMo
         }
         ProcessBuilder depModuleSubprocess =
             new ProcessBuilder()
-                .command("java", "-jar", DEP_MODULE_MONOMORPHIZATION_SUBPROCESS_BINARY_PATH,
+                // .command("/private/var/tmp/_bazel_jasonsteving/895b6e2a5639ccc5f59fc3ca15e75bfa/external/rules_java~5.5.1~toolchains~remotejdk11_macos_aarch64/zulu-11.jdk/Contents/Home/bin/java", "-jar", DEP_MODULE_MONOMORPHIZATION_SUBPROCESS_BINARY_PATH,
+                .command("{{BAZEL_JAVA_PATH}}", "-jar", DEP_MODULE_MONOMORPHIZATION_SUBPROCESS_BINARY_PATH,
                          "--coordinator_port", String.valueOf(coordinatorPort),
                          "--dep_module_file_path", DEP_GRAPH_CLARO_MODULE_PATHS_BY_UNIQUE_MODULE_NAME.get(uniqueModuleName),
                          // TODO(steving) DELETE THIS, The uniqe name should be looked up in the .claro_module.
@@ -190,7 +191,7 @@ private static ListenableFuture<DepModuleMonomorphizationService> getDepModuleMo
                 .redirectOutput(ProcessBuilder.Redirect.INHERIT)
                 .redirectError(ProcessBuilder.Redirect.INHERIT);
         depModuleSubprocess.environment().putAll(RUNFILES_ENV_VARS);
-        depModuleSubprocess.start();
+	depModuleSubprocess.start();
       } catch (IOException e) {
         throw new RuntimeException(
             "Internal Compiler Error! Unable to start dep module monomorphization subprocess for module: " +